Geotechnical Contract Baseline No. PS 4350 Report 2000

WESTSIDE SUBWAY EXTENSION PROJECTContract No. PS‐4350‐2000

Westside Subway Extension Project, Section 1 Contract C1045

Geotechnical Baseline Report Amendment 3 October 15, 2013 May 22, 2013

Los Angeles County Metropolitan Authority C1045 Westside Subway Extension Project, Section 1

Geotechnical Baseline Report

Prepared for:

Prepared by:

777 South Flower Street, Suite 1100 Los Angeles, CA 90017 Amendment 3 October 15, 2013 May 22, 2013

Summary of Revisions to the May 22, 2013 GBR

Section/Figure /Table

Revision Page Nos.

Section 1.1 Revision to identify where baseline statements are found in GBR. 1‐1, 1‐2

Section 1.2 Update of status of ongoing investigations 1‐2

Section 2.0 Clarification of information source and update of Figure 2‐1 2‐1, 2‐2, 2‐3

Section 3.0 Revision to indicate purpose of section and to identify where baseline statements are found in GBR.

3‐1

Section 3.1 Clarification of text 3‐1


Section 3.3.5 Update of information 3‐3

Section 3.4 Clarification of text 3‐3, 3‐4

Section 3.5 Deletion of term ”perched” groundwater 3‐4

Section 3‐7 Deletion of Figure 3‐1 and correction of explosive limits for methane 3‐5

Section 4.0 Revision to indicate purpose of section and to identify where baseline statements are found in GBR.

4‐1

Section 4‐1 Clarification of text and deletion of reference to Appendix C 4‐2

Section 4‐2 Deletion of discussion of asphalt content in coarse‐ versus fine‐grained materials and revision of asphalt content ranges for different soil/bedrock types

4‐3, 4‐4

Section 4‐3 Clarification of text 4‐6

Section 4‐4 Correction of Metro study dates Change of “perched” to semi‐perched” groundwater Deletion of discussion of monitoring of gas wells Correction of the boundaries for the elevated gas zone Clarification of text Update of Figures 4‐5 and 4‐6

4‐74‐7 4‐9 4‐9 4‐9, 4‐10 4‐11, 4‐12

Section 5.1 Update of source of building information and tieback information 5‐1, 5‐2


Section 5.3 Clarification of text and move of text to Section & related to “Salt Lake” 10 Oil Well

5‐3, 5‐4

Section 5.4 Clarification of text and deletion of quantity of asphalt impacted soil 5‐4, 5‐5

Section 6.0 Revision to identify the responsibility of Design‐Build Contractor to establish design parameters

6‐1

Section 6.1 Clarification of text 6‐1, 6‐2

Section 6.1.2 Clarification of text 6‐2

Section 6.2 Update information 6‐2


Section 6.3 Update information 6‐3



Section 6.5.2 Deletion of Section titled “TBM Selection” 6‐6, 6‐7


Section 6.5.4 Clarification of text and addition of discussion about test procedure for asphalt impacted soils

6‐9




Section 6.8 Clarification of text and discussion of limits of gas remediation measure effectiveness

6‐11, 6‐12

Section/Figure /Table

Revision Page Nos.


7‐1


Section 7.1.1 Update information 7‐1

Section 7.1.2 Deletion of reference to hydraulic conductivity 7‐2

Section 7.1.3 Deletion of reference to tar sands 7‐2


Section 7.2.2 Update of information 7‐3

Section 7.2.3 Deletion of reference to Exploratory Shaft off gassing. Data has been made available in Field Observations Report – September 30th, 2013

7‐4

Section 7.3 Deletion of “shotcrete”. GBR does not specify material 7‐5

Section 7.3.1 Clarification of text and update of information 7‐5

Section 7.3.2 Update on information 7‐6

Section 7.3.3 Change of “perched” to semi‐perched” groundwater and update of Metro reference

7‐6, 7‐7

Section 7.3.4 Update description of “asphalt” 7‐7

Section 7.3.5 Update Information 7‐7

Section 7.4.2 Update of information 7‐8, 7‐9


Section 7.6 Update of information 7‐10, 7‐11

Section 7.7 Update of information 7‐11



Section 7.9 Revision to identify the responsibility of Design‐Build Contractor to establish design parameters and text clarification

7‐14


8‐1

Section 8.1.9 Revision to identify baseline conditions 8‐3



Section 10.0 Update References 10‐3

Appendix B Update – Figures to include the latest field and laboratory data B5, B6, B7, B8, B9, B15, B25, B26, B27, B28, B29, B30, B32, B33, B34, B35, B36, B37, B38

Appendix C Deletion of appendix and its replacement in its entirety All

Appendix D Change in Title to Summary of Chemical Constituents in Ground and Groundwater


Table of Contents

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Table of Contents

1.0 INTRODUCTION .................................................................................................................... 1‐1

1.1 Purpose of GBR ................................................................................................................ 1‐1

1.2 Subsurface Investigations ................................................................................................ 1‐2

2.0 PROJECT DESCRIPTION .......................................................................................................... 2‐1

2.1 Alignment ......................................................................................................................... 2‐1

2.2 Anticipated Site for Tunneling Operations ...................................................................... 2‐2

3.0 GEOLOGIC SETTING AND SUBSURFACE CONDITIONS ............................................................. 3‐1

3.1 Geologic Setting ............................................................................................................... 3‐1

3.2 Local Faulting and Folding ............................................................................................... 3‐1

3.3 Subsurface Materials along Section 1 Alignment ............................................................ 3‐2 3.3.1 Younger Alluvium ................................................................................................ 3‐2 3.3.2 Older Alluvium .................................................................................................... 3‐2 3.3.3 Lakewood Formation .......................................................................................... 3‐2 3.3.4 San Pedro Formation .......................................................................................... 3‐3 3.3.5 Fernando Formation ........................................................................................... 3‐3

3.4 Asphalt Impacted Geologic Formations ........................................................................... 3‐3

3.5 Groundwater .................................................................................................................... 3‐4

3.6 Oil Fields ........................................................................................................................... 3‐4

3.7 Subsurface Gases ............................................................................................................. 3‐5

4.0 ENGINEERING CHARACTERIZATION ....................................................................................... 4‐1

4.1 Soils Characterization ...................................................................................................... 4‐1

4.2 Asphalt Characterization .................................................................................................. 4‐2

4.3 Ground and Groundwater Chemistry ........................................................................ 4‐54‐4

4.4 Gas Characterization .................................................................................................. 4‐74‐6

5.0 MAN MADE FEATURES OF CONSTRUCTION SIGNIFICANCE .................................................... 5‐1

5.1 Structures along the Alignment ....................................................................................... 5‐1

5.2 Utilities ....................................................................................................................... 5‐35‐2

5.3 Abandoned Oil Wells and Facilities .................................................................................. 5‐3

5.4 Ground and Groundwater Contamination ................................................................ 5‐45‐3

6.0 TBM TUNNELS ...................................................................................................................... 6‐1

6.1 Tunnel Reach 1 ‐ Wilshire/Western Access Shaft to Wilshire/La Brea Station ............... 6‐1 6.1.1 Groundwater ................................................................................................. 6‐26‐1

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6.1.2 Gases ................................................................................................................... 6‐2

6.2 Tunnel Reach 2 ‐ Wilshire/La Brea Station to Wilshire/Fairfax Station ........................... 6‐2 6.2.1 Groundwater ....................................................................................................... 6‐3 6.2.2 Gases ................................................................................................................... 6‐3

6.3 Tunnel Reach 3 ‐ Wilshire/Fairfax Station to Wilshire/La Cienega Station ..................... 6‐3 6.3.1 Groundwater ....................................................................................................... 6‐4 6.3.2 Gases ................................................................................................................... 6‐4

6.4 Tail Tracks Tunnel Reach ‐ West of La Cienega Station ................................................... 6‐4 6.4.1 Groundwater ................................................................................................. 6‐56‐4 6.4.2 Gases ................................................................................................................... 6‐5

6.5 TBM Excavation ............................................................................................................... 6‐5 6.5.1 Closed Face TBMs ............................................................................................... 6‐5 6.5.2 Soil Abrasion ................................................................................................. 6‐76‐6 6.5.3 Soil Stickiness ................................................................................................ 6‐86‐7

6.6 Ground Support in Tunnels ........................................................................................ 6‐96‐8 6.6.1 Tunnel Lining ................................................................................................. 6‐96‐8 6.6.3 Break‐Outs and Break‐Ins with TBM ........................................................... 6‐106‐9

6.7 Spoil Handling and Disposal ..................................................................................... 6‐106‐9 6.7.1 Spoil Handling ............................................................................................. 6‐106‐9 6.7.2 Spoil Characterization ............................................................................... 6‐116‐10

6.8 Gas Control ............................................................................................................ 6‐116‐10

7.0 SHAFT AND STATIONS EXCAVATIONS ................................................................................... 7‐1

7.1 Wilshire/Western Retrieval Shaft .................................................................................... 7‐1 7.1.1 Subsurface Conditions at the Excavation at Wilshire/Western Shaft ................ 7‐1 7.1.2 Groundwater ................................................................................................. 7‐27‐1 7.1.3 Gases ................................................................................................................... 7‐2

7.2 Wilshire/La Brea Station Excavation ................................................................................ 7‐2 7.2.1 Subsurface Conditions at the Excavation at Wilshire/La Brea Station ......... 7‐37‐2 7.2.2 Groundwater ....................................................................................................... 7‐3 7.2.3 Gases ................................................................................................................... 7‐4

7.3 Wilshire/Fairfax Station Excavation ................................................................................. 7‐4 7.3.1 Subsurface Conditions at the Excavation at Wilshire/Fairfax Station .......... 7‐57‐4 7.3.2 Paleontological Monitoring Zone ................................................................. 7‐67‐5 7.3.3 Groundwater ....................................................................................................... 7‐6 7.3.4 Asphalt ................................................................................................................ 7‐7 7.3.5 Gases ................................................................................................................... 7‐7

7.4 Wilshire/La Cienega Station ....................................................................................... 7‐87‐7 7.4.1 Subsurface Conditions at the Excavation at Wilshire/La Cienega Station .... 7‐87‐7 7.4.2 Groundwater ....................................................................................................... 7‐8 7.4.3 Gases ................................................................................................................... 7‐9


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7.5 Initial Ground Support at Station and Shaft Excavations ........................................ 7‐107‐9

7.6 Anticipated Ground Behavior at Excavations .......................................................... 7‐107‐9

7.7 Excavation Methods .............................................................................................. 7‐117‐10 7.7.1 Drilling for Soldier Piles ............................................................................. 7‐117‐10 7.7.2 Shaft Excavation ........................................................................................ 7‐127‐11

7.8 Gas Controls ........................................................................................................... 7‐137‐12

7.9 Permanent Station Structures ............................................................................... 7‐147‐12

8.0 MINED EXCAVATIONS ........................................................................................................... 8‐1

8.1 Cross Passages and Cross Passages with Sump Structures .............................................. 8‐1 8.1.1 Subsurface Conditions ........................................................................................ 8‐1 8.1.2 Groundwater ....................................................................................................... 8‐1 8.1.3 Gases ................................................................................................................... 8‐1 8.1.4 Ground Improvement ......................................................................................... 8‐1 8.1.5 Method of Excavation ......................................................................................... 8‐2 8.1.6 Initial Ground Support ........................................................................................ 8‐2 8.1.7 Anticipated Ground Behavior during Construction ............................................ 8‐3 8.1.8 Gas Controls ........................................................................................................ 8‐3 8.1.9 Permanent Structural Lining ............................................................................... 8‐3

9.0 BUILDING AND UTILITY PROTECTION MEASURES .................................................................. 9‐1

9.1 Assessment of Settlements .............................................................................................. 9‐1 9.1.1 Settlements caused by TBM driven Tunnels ....................................................... 9‐1 9.1.2 Settlements Adjacent to Open‐Cut Construction ............................................... 9‐1

9.2 Protection of Structures and Utilities .............................................................................. 9‐2

10.0 REFERENCES ....................................................................................................................... 10‐1

10.1 Geotechnical Baseline Report References ..................................................................... 10‐1

List of Figures Figure 2‐1: Tunnel Reaches within Section 1 ............................................................................................. 2‐3

Figure 4‐1: Distillation Product of Asphalt from the Asphalt Impacted Soils ...................................... 4‐34‐2

Figure 4‐2: Viscosity/Temperature Relationship ................................................................................. 4‐44‐3

Figure 4‐3: Asphalt Content versus Depth ........................................................................................... 4‐54‐4

Figure 4‐4: City of Los Angeles Methane and Methane Buffer Zone Map showing Section 1 of WSE 4‐84‐7

Figure 4‐5: Potential Methane Off Gas Volume ............................................................................... 4‐114‐10

Figure 4‐6: Potential Hydrogen Sulfide Off Gas Volume .................................................................. 4‐124‐11

Figure 6‐1: Assessment of Clogging Potential ...................................................................................... 6‐86‐7


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List of Tables Table 4‐1: Asphalt (Tar) Content Classification .......................................................................................... 4‐3

Table 5‐1: Tiebacks expected to Intrude into Station Excavations and Tail Track Tunnels ....................... 5‐2

Table 5‐2: Foundations for Buildings Demolished as Part of Contract ...................................................... 5‐2

Table 5‐3: Oil Wells along Alignment ......................................................................................................... 5‐3

Table 5‐4: Summary of Boring Locations and Suspect Sources for Hazardous Materials ................... 5‐65‐5

Table 6‐1: Classification of Abrasiveness of Soil and Rock .................................................................. 6‐76‐6

Table 6‐2: Abrasion Test Results by Geologic Formations ................................................................... 6‐86‐6

Table 9‐1: Impact Categories for Open‐Cut Construction ......................................................................... 9‐1

List of Appendices

APPENDIX A GEOLOGIC PROFILE ................................................................................................... A‐1

APPENDIX B ENGINEERING CHARACTERIZATION OF SOILS AND ROCK .......................................... B‐1

APPENDIX C ENGINEERING PROPERTIES ....................................................................................... C‐1

APPENDIX D SUMMARY OF CHEMICAL CONSTITUENTS IN GROUND AND GROUNDWATER ........... D‐1

APPENDIX E SUPPLEMENTARY DISCUSSION OF GAS MONITORING .............................................. E‐1

APPENDIX F LOS ANGELES TUNNELING EXPERIENCE ..................................................................... F‐1

APPENDIX G GLOSSARY OF TERMS ............................................................................................... G‐1


1.0 - Introduction

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1.0 INTRODUCTION

This Geotechnical Baseline Report (GBR) presents the subsurface conditions anticipated during construction of underground work for Section 1 of the Westside Subway Extension (WSE) in Los Angeles. This project will extend the Heavy Rail subway system for the Los Angeles Metro Purple Line from the existing Wilshire/Western Station westward to a station in the vicinity of Wilshire/La Cienega. The project is being built for Los Angeles County Metropolitan Transportation Authority (Metro).

The underground work includes bored tunnels, station excavations as well as cross‐passages and sump structures. These structures are to be constructed in the alluvial soils and weak sedimentary bedrock of the Los Angeles Basin. Since the work will take place in an urban area, the protection of existing structures and buried utilities that could be impacted is critical to the successful completion of the work.

Geotechnical baselines are provided in Sections 6, 7 and 8 and Appendices A and B of this GBR. All other information is for background only. Ground behavior described in the GBR is based on assumptions regarding construction means and methods. If different methods are employed, ground behavior may differ from that described. The Design‐Builder Contractor must complete its own independent review and evaluation of the Contract Documents, GBR, Geotechnical Data Reports (GDRs), and other geotechnical information and consider how its selected means and methods and designs will affect ground behavior and the construction of the underground facilities. Proper geotechnical and civil design requires that materialgeotechnical parameters be selected based on representative exploration data and test results and geologic information and that the inherent variability of geologic materials be taken into account in selecting probable ranges of soilgeotechnical parameters to be incorporated into the design process.

The GBR is contractually binding and must be read in conjunction with the GDRs and other Contract Documents. While the GBR is not the exclusive source of geotechnical information, in the event of a differing ground condition claim, Article 1 of the Contract provides that the GBR takes precedence over the GDRs, as well as any other geotechnical information, references or interpretations.

1.1 Purpose of GBR This GBR is issued by Metro as part of the Design‐Build Contract Documents for construction of the underground facilities for Section 1. It is prepared on the basis of an evaluation and interpretation of geotechnical data obtained from subsurface investigations.

The objectives of the GBR are to:

1. Provide a summary of the ground conditions, ground behavior, groundwater, in‐ground obstructions, contamination, and gas conditions in order to facilitate an understanding of the geotechnical features and ground behavior to be addressed during proposal preparation and during design and construction of the underground facilities by the project management teams from the Design–Builder Contractor and Metro.

2. Establish baselines for the anticipated geotechnical conditions and basic tunnel ground behavior to be relied upon in the preparation of proposals, in bid submittals, and in the design and the construction of the underground facilities.


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Geotechnical Baseline Report 1.0 – Introduction

3. Assist in administering the differing site conditions clause contained in the Contract Documents by providing a basis for evaluation.

Ground behavior described in the GBR is based on assumptions regarding construction means and methods. If different methods are employed, ground behavior may differ from that described. The Design‐Builder must complete its own independent review and evaluation of the Contract Documents, GBR, Geotechnical Data Reports (GDRs), and other geotechnical information and consider how its selected means and methods and designs will affect ground behavior and the construction of the underground facilities.

Proper geotechnical and civil design requires that material parameters be selected based on representative exploration data and test results and geologic information and that the inherent variability of geologic materials be taken into account in selecting probable ranges of soil parameters to be incorporated into the design process.

The GBR is contractually binding and must be read in conjunction with the GDRs and other Contract Documents. While the GBR is not the exclusive source of geotechnical information, Article 1 of the Contract provides that the GBR takes precedence over the GDRs, as well as any other geotechnical information, references or interpretations.

1.2 Subsurface Investigations The data developed during the subsurface investigations are documented in the Geotechnical Data Reports (GDRs) and Environmental Data Reports (EDR) prepared for the Section 1 tunnels, and shaft and station excavations (Metro, 2011; Metro, 2013a‐h). The data were developed from: borings including boring logs and inspection of borehole samples; laboratory testing; review of regional and local geology; and, review of previous experience of drilling, excavating, and tunneling in Los Angeles. Preliminary evaluations of the geotechnical data are documented in the Geotechnical Design Memoranda prepared for the Section 1 tunnels and shaft and station excavations (Metro 2013j‐m).

An exploratory shaft is planned for constructionbeing constructed (by others) near the Wilshire/Fairfax station site. Its goals are to: characterize the asphalt impacted ground; characterize gas conditions; and, better understand constructability issues, particularly related to excavation in ground potentially containing fossilized remains (refer to Metro 2012 a‐c for further details regarding the Exploratory Shaft contract). It is anticipated that as the exploratory shaft is excavated and data from the construction are collected, they will be made available to the prospective Design‐Build Teams.

As of the date ofDuring the preparation of this GBR, additional subsurface investigations are plannedwere carried out. They will provide further information on the Fernando Formation including characterization of discontinuities within the formation and their potential as a source of gas. This The information assists with will allow consideration of a deeper profile for the tunnels by the prospective Design‐Build Teams, and additional characterization of gas conditions within Section 1. The results of these investigations will be given to the prospective Design‐Build Teams as they become available.


2.0 - Project Description


2.0 PROJECT DESCRIPTION

Section 1 of the WSE (refer to Figure 2‐1) extends approximately 3.9 miles underground beneath Wilshire Boulevard from a shaft at the western end of the existing Wilshire/Western Station to the vicinity of the intersection of Wilshire Boulevard and South Stanley Street – to the west of La Cienega Boulevard. The section lies within two local jurisdictions – the City of Los Angeles and the City of Beverly Hills. The tunnels follow an east‐west alignment with stations located near the intersections of: Wilshire Boulevard and La Brea Avenue; Wilshire Boulevard and Fairfax Avenue; and, Wilshire Boulevard and La Cienega Boulevard.

Twin subway tunnels, one for each direction of travel will be constructed. Tunnels will each have an inside diameter of not less than 18‐feet 10‐inches. The tunnels are up to approximately 100 feet below ground (to the tunnel crown) and are separated by a pillar approximately seventeen feet widealignment and profile are shown on the Project Definition Drawings.

2.1 Alignment Section 1 follows an alignment through a built‐up area that is characterized by paved streets, commercial office buildings, retail businesses, medical office buildings, museums, and apartments and condominiums. The following is a general description of the alignment:

Wilshire/Western Shaft ‐ The Wilshire/Western shaft will be located just west of the existing Wilshire/Western Station. It will be in Wilshire Boulevard and an adjacent vacant property to the north that is about 75 feet east of Manhattan Place. The shaft will facilitate connection of the WSE tunnels to the existing Wilshire/Western Station and will be used to retrieve the TBMs at the completion of tunneling for Reach 1. After completion of tunneling, the upper part of the shaft will be backfilled.

Existing one story buildings are located in the vicinity of the shaft site. Some of the buildings have basement levels up to a depth of 12 feet below ground surface. The existing Wilshire/Western Station is located about 20 feet east of the shaft.

Tunnel Reach 1: Wilshire/Western Shaft to Wilshire/La Brea Station ‐ From Wilshire/Western, the tunnels will run beneath Wilshire Boulevard westward to Wilshire/La Brea Station. The properties on Wilshire Boulevard within the reach consist of commercial and office buildings, and condominiums and apartments.

Wilshire/La Brea Station ‐ The excavation for the Wilshire/La Brea Station and the double crossover box to its east will be located on Wilshire Boulevard between Mansfield Avenue and South Detroit Street. The surrounding area comprises primarily commercial properties and apartment buildings.

Tunnel Reach 2: Wilshire/La Brea Station to Wilshire/Fairfax Station ‐ The tunnels will continue beneath Wilshire Boulevard going due west from Wilshire/La Brea Station to Wilshire/Fairfax Station. The properties along Wilshire Boulevard within this reach consist generally of commercial buildings, condominiums, apartments and office buildings.

Wilshire/Fairfax Station ‐ The excavation for the Wilshire/Fairfax Station will be located on Wilshire Boulevard between Fairfax Avenue and Ogden Drive. This is in the vicinity of “Museum Row” and the La Brea Tar Pits. Museums in this area include Petersen Automotive Museum, Los Angeles County Museum


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Geotechnical Baseline Report 2.0 – Project Description

of Art, (LACMA), A+D Museum, Craft and Folk Art Museum, and the Page Museum. The La Brea tar pits are locations where fossil deposits have been found preserved in asphalt impacted ground.

Tunnel Reach 3: Wilshire/ Fairfax Station to Wilshire/La Cienega Station – The tunnels will continue beneath Wilshire Boulevard going westward from Wilshire/Fairfax Station to Wilshire/La Cienega Station. Properties adjacent to the alignment in this reach are mainly commercial and office buildings, several of which are high‐rise buildings.

Wilshire/La Cienega Station ‐ The excavation for the Wilshire/La Cienega Station will be located on Wilshire Boulevard between La Cienega Boulevard and South Tower Drive. The properties adjacent to the station consist of commercial /office buildings.

Tail Track Tunnels west of Wilshire/La Cienega Station – The tunnels will continue westward beyond the Wilshire/La Cienega Station for approximately 700 feet. These tail track tunnels provide for train storage when only Section 1 is operational. They will be incorporated into Section 2 of the WSE as running tunnels for the subway system.

Cross Passages – Cross passages connecting the east and west bound tunnels are required at a spacing of about 800 feet. These provide emergency evacuation routes in the event of a train malfunction (or other emergency) and locations for equipment necessary to operate the subway system. For the Section 1 alignment, there will be 23 cross passages, of which three (located at low points) also serve as sump structures equipped with pumps discharging to surface facilities.

2.2 Anticipated Site for Tunneling Operations Metro is providing staging area at Wilshire/La Brea anticipating that the Wilshire/La Brea excavationand this will be the site for launching TBMs and mining the tunnels. The staging area to be made available at Wilshire/La Brea is presented on the Project Definition Drawings.

It is anticipated that the Wilshire/Western shaft will be used during construction to make the connection into the existing station and to provide access underground for removal of the tunnel boring machines at the completion of tunnel drives to Wilshire/Western. The shaft will be backfilled and there will no permanent access from the surface to the tunnels at the shaft location


2.0 - Project Description

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Figure 2-1: Tunnel Reaches within Section 1


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Geotechnical Baseline Report 2.0 – Project Description

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3.0 – Geologic Setting and Subsurface Conditions


3.0 GEOLOGIC SETTING AND SUBSURFACE CONDITIONS

This section provides an overview of the regional geologic setting and subsurface conditions. Project specific baselines are provided in Sections 6, 7 and 8 and Appendices A and B.

3.1 Geologic Setting Southern California’s Peninsular Ranges and Transverse Ranges geomorphic provinces form the geologic setting for the project. Each province has its own distinct structural and geomorphic features with the Santa Monica and Hollywood faults considered to be the boundary between them. The Peninsular Ranges province (to the south) is characterized by elongated northwest‐southeast trending geologic structures such as the Newport‐Inglewood fault zone. In contrast, the Transverse Ranges province (to the north) is characterized by east‐west trending geologic structures such as the Santa Monica fault, the Hollywood fault, and the Santa Monica Mountains. The Section 1 alignment is approximately 3 miles south of the Santa Monica Mountains.

The Los Angeles Basin occupies the northernmost portion of the Peninsular Ranges and the south part of the Transverse geomorphic provinces. This sedimentary basin is a major elongated northwest‐trending structural depression that has been filled since the middle Miocene with sediments up to 31,000 feet thick.

Gently sloping alluvial plains extending south from the Santa Monica Mountains were formed by accumulation of sediments shed from the mountain front over the course of the late Pleistocene epoch and by tectonic uplift along the eastern portion of the Santa Monica Mountain range front. The result was the development of alluvial surfaces at varying elevations and ages adjacent to the mountain front. Older alluvial surfaces are generally located at higher elevations and show greater dissection by stream channels.

The deep sedimentary Los Angeles basin is known as a major source of hydrocarbons. The rocks and soils overlying the hydrocarbon deposits contain naturally occurring products that include methane, other hydrocarbons and hydrogen sulfide and hydrocarbons. These products have migrated upward from the deeper formations through discontinuities (fractures and faults) in the bedrock and through the soils. They have impacted the groundwater, and also the near‐surface soils both below and above the groundwater table. The hydrocarbon impacted soils are predominantly found in the Mid‐Wilshire area between South Dunsmuir Avenue and South Crescent Heights Boulevard. Asphalt seeps (locally referred to as tar seeps) and the La Brea Tar Pits in Hancock Park illustrate this upward migration of hydrocarbons.

3.2 Local Faulting and Folding Southern California is a seismically active region, well known for its active faults and historic seismicity. Active faults near the Section 1 alignment include: the Hollywood Fault, approximately two and one half miles north; the Newport‐Inglewood Fault Zone (and associated West Beverly Hills Lineament) approximately three miles to the west‐south‐west; and, the Santa Monica Fault approximately three and one half miles to the west (refer to Fig 3‐1 in Metro 2013e). There are no known active faults crossing the Section 1 alignment.


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Geotechnical Baseline Report 3.0 – Geologic Setting and Subsurface Conditions

The inactive Third and Sixth Street Faults are found to the northin the vicinity of Wilshire Boulevard in the Fairfax District. They are is considered to be flow paths for asphalt seeps in the vicinity of Hancock Park that have also formed the La Brea Tar Pits.

3.3 Subsurface Materials along Section 1 Alignment The geologic units present along the Section 1 alignment are as follows:

3.3.1 Younger Alluvium

The Younger Alluvium (symbol on geologic profiles: Qal) forms surficial cover along parts of the alignment. It has been deposited by alluvial fan processes and as deposits in relatively narrow, south‐flowing drainage courses, which are incised into the underlying Older Alluvium and Lakewood Formation.

Where encountered in exploratory borings, the deposits consist of brown and dark brown poorly consolidated, inter‐layered silts, sandy to silty clays, and silty sands with lenses of sandy silt and gravelly sand. The thickness of Younger Alluvium within Section 1 ranges up to about 30 feet.

3.3.2 Older Alluvium

The Older Alluvium (symbol on geologic profiles: Qalo) deposits consist of sediments deposited by sheet flow and by former streams. These deposits derive mainly from the Santa Monica Mountains to the north. They are near surface deposits of relatively limited extent with respect to the project and, where found vary from about 15 feet up to 35 feet thick.

Where encountered in borings, the Older Alluvium generally consists of brown and gray, loose to dense sands and gravels (stream channel deposits) and interbedded predominantly gray and brown to olive gray, medium stiff to hard silts and clays, and gravelly silts and clays(fan and overbank deposits). Although local channels with abundant gravel and occasional cobbles are present, boulders were not encountered in the borings drilled along the tunnel alignment.

Since the Older Alluvial deposits and the underlying Lakewood Formation are compositionally similar, a clear contact between them is often difficult to distinguish.

3.3.3 Lakewood Formation

The Lakewood Formation forms the surficial cover at the eastern half portion of the tunnel alignment (symbol on geologic profiles: Qlw). The thickness of the Lakewood Formation varies from approximately 5 feet to about 50 feet.

Where encountered in borings, these sediments consist predominantly of interbedded yellow and brown to light to medium gray colored silty sands, poorly graded sands, silts and clays with some clayey sand layers and some layers and zones of gravel and occasional cobbles. The Lakewood Formation is generally dense where granular and very stiff to hard where consisting of silts and clays.

The base of the Lakewood Formation is often indicated by layers having lateral continuity that contain bivalve shell fragments.




3.3.4 San Pedro Formation

Marine sediments of the San Pedro Formation (symbol on geologic profiles: Qsp) unconformably underlie the Lakewood Formation and Older Alluvium. The San Pedro Formation ranges from approximately 15 to 60 feet below ground surface with its thickness increasing from east to west from about 20 feet to more than 100 feet.

Where encountered in borings, the San Pedro Formation consists of interbedded light to dark greenish‐gray and bluish gray, fine‐grained dense micaceous sand and silty sand, with interbeds of medium‐ to coarse‐grained sand and stiff to hard silt layers. Occasional cobbles, gravelly sand layers and shell fragments are also present. A number of fossiliferous beds containing bivalve shell fragments occur within the San Pedro Formation. Local lenses and more continuous layers of hard to very hard concretionary deposits strongly cemented with calcium carbonate are present.

3.3.5 Fernando Formation

Sedimentary bedrock of the Fernando Formation (symbol on geologic profiles: Tf) unconformably underlies the San Pedro Formation at depths ranging from between 65 and 105 feet below ground surface.

The Fernando Formation consists of predominantly massive with occasional subvertical jointing, stiff to hard, yellow‐brown to olive‐gray friable, extremely weak to weak siltstone and claystone with slight weathering found in its upper ten feet. Sedimentary bedding within the formation is generally poorly developed to locally, moderately well‐developed.

The formation contains thin sandstone interbeds and laminations, cobble and boulder sized concretions and nodules that are moderately to strongly cemented with calcium carbonate and range in strength from weak to strong (700 ‐ 14,500 psi). The cemented layers or lenses, range in thickness from a few inches to 3 feet and must be assumed to be continuous laterally.

The siltstone/claystone has a void ratio in the range of 0.64 to 1.79 and as the Fernando Formation is below the groundwater table, the voids are saturated. The water content for the siltstone/claystone ranges from 19 to 85 percent.

3.4 Asphalt Impacted Geologic Formations Soils naturally impacted with asphalt (locally referred to as “tar sands”) are found in the Younger and Older Alluvium, Lakewood, San Pedro, and Fernando Formations. They occur in the reach along Wilshire Boulevard, between South Dunsmuir Avenue and South Crescent Heights Boulevard, a distance of about 0.94 miles. The tar sands do not represent a separate geologic unit but can be expected to have different characteristics to those normally associated with soils not impacted with asphalt.

The impregnation results from seeps of heavy oil fractions. These heavy oil fractions are a complex and continuous mixture of diverse organic compounds, spanning a wide molecular weight/carbon number range (Boduszynski et al., 1998). Near the surface, the heavy oil becomes asphaltic as the lighter fractions of the hydrocarbon products biodegrade or vent.

The oil seeps up through vents, fissures and fractures in the ground from the Salt Lake Oil Field that underlies much of the Fairfax district north in the vicinity of Hancock Park. The fractures are thought to


May 22, 2013 Page 3-4


be associated with the Third and Sixth Street Faults. The asphalt is found seeping up to the ground surface and active seeps can be viewed in Hancock Park, near the proposed Wilshire/Fairfax Station. The La Brea Tar Pits represent a well known surface example of the presence of asphalt in the area. At the tar pits, localized pools of asphalt have accumulated and the fossilized remains of animals trapped in the tar are commonly found.

Within the soils, the asphalt has mostly impregnated the pore spaces of the Alluvium, Lakewood and San Pedro and Fernando Formations. However, in some places, the asphalt has hardenedis contained within fissures as it oozes upwards forming hardened asphaltic rich pipes, pockets and mounds. In addition, asphalt has in places impregnated the overlying surface fill. The Fernando Formation also contains asphalt within its pore spaces and within discontinuities (such as joints, vents, fissures and fractures) in the formation.

As described above, locally, these asphalt impacted soils are referred to as “tar sands”. However, the term “sand” does not fully capture the full range of particle sizes for materials found impacted. The Alluvium, Lakewood and San Pedro Formations are heterogeneous geologic units comprising interbedded layers and lenses of fine‐ and coarse grained materials. As a result, as well as “sand layers and lenses”, the asphalt impacted soils contain layers and lenses of fine grained soils, typically sandy silts, sandy clays, and silty clays and these are sometimes differentiated by the term “Petroliferous Silts/Clays” in the technical literature. Where the term “tar sand” is used in this report and the GDRs, it refers to the impacted soils regardless of grain size distribution.

3.5 Groundwater The alignment lies within the Central Basin, one of the four major hydrogeologic basins of the coastal plain of Los Angeles County. Groundwater in this basin is found within aquifers in the Lakewood and San Pedro Formations. These water bearing zones consist of permeable sands and gravels that are separated by more impermeable sandy clay and clay layers.

Shallow groundwater is found within the Younger and Older Alluvium and Lakewood Formation. This is semi‐perched or perched water that is trapped in permeable zones underlain by less permeable zones. Where asphalt impacted soils are found, because they form relatively impermeable layers, semi‐perched groundwater conditions also occur.

The Alluvium, Lakewood, San Pedro and Fernando Formations below the groundwater table are saturated and fluids (including water, gases and asphalt) within these formations will be under a fluid pressure at least equivalent to the hydrostatic head. Artesian conditions also exist as a result of groundwater trapped below more impermeable layers. Semi‐confined groundwater and artesian conditions can occur in sands and gravels where these layers are both above and below less permeable layers.

Groundwater levels are influenced by seasonal rainfall and infiltration and by nearby groundwater extraction. Groundwater levels fluctuate due to both seasonal changes and manmade influences.

3.6 Oil Fields The alignment passes through portions of the South Salt Lake Oil Field, as mapped by the California Department of Conservation, Division of Oil, Gas and Geothermal Resources (DOGGR). As a result of the




development of the oil field, oil wells – active and abandoned –have been identified within, or close to the alignment corridor.

Oil field boundaries are shown on Figure 4‐44 of Metro, 2012a. However, the natural migration of oil and gas along faults, fractures, bedding planes and permeable sediments means that the identified boundaries of the oil fields do not limit the locations where gas and oil seeps occur.

3.7 Subsurface Gases Methane and hydrogen sulfide are found in gaseous form and dissolved in groundwater and asphalt in the pore spaces found within the fill, Younger and Older Alluvium, Lakewood and San Pedro Formations, and in both pore space and discontinuities (joints, bedding planes and fractures) within the Fernando Formation. Isotopic analysis of methane samples collected from gas probes along the alignment suggest the gas is predominantly of thermogenic origin consistent with an oil field source (see Figure 3‐1) and are seeping up from the hydrocarbon deposits below. However, bacterial breakdown of hydrocarbons seeping towards the ground surface has also been put forward as a source of origin in the vadose zone (Kim and Crowley, 2007).

Figure 3-1: Isotopic Analysis of Methane Samples

The upward gas migration is relatively unrestricted within the Fernando Formation (through fractures) and the gas accumulates within the upper portion of the overlying saturated sandy materials beneath a cap of saturated, finer grained alluvial deposits. As the gas collects, it tends to pressurize the zone within which it accumulates. The over‐pressurization is limited to the incremental pressure needed to induce seepage through the cap material.


May 22, 2013 Page 3-6


Methane is common in oil and gas fields and is often found with hydrogen sulfide gas. Methane gas is explosive when its concentration is between five and twelve fifteen percent at atmospheric oxygen levels but is not highly toxic. Rather, it asphyxiates as it displaces oxygen. Methane (density ~0.72 g/l at atmospheric pressure) is lighter than air and it tends to rise through the ground and dissipate. Methane is moderately soluble in water.

Hydrogen Sulfide is produced by the anaerobic decomposition of organic and inorganic matter that contains sulfur. It is highly toxic when inhaled. Its flammable range is at concentrations between four and 46 percent and it is corrosive. Hydrogen sulfide (density ~1.54 g/l at atmospheric pressure) is heavier than air and within the ground tends to accumulate above the groundwater table and within depressions. It is highly soluble in water.

Anaeorobic conditions typically prevail in the subsurface when significant levels of biodegradable organic compounds – such as asphalt, oil, or plant materials – are present. Methane and carbon dioxide are typically present at approximately equal concentrations in this setting and often account for nearly all of the gas in the soil.


4.0 – Engineering Characterization


4.0 ENGINEERING CHARACTERIZATION

This section provides an overview of the soil and gas conditions that can be expected. It is for information only with specific baselines provided in Sections 6, 7 and 8 and Appendices A and B.

4.1 Soils Characterization The geologic units to be encountered in the underground excavations are heterogeneous soils and weak rock deposits. Soil and rock descriptions have been based on visual logging of cores and samples, review of sonic core log photographs, SPT and CPT data, and laboratory index testing.

The soils (Alluvial Soils, Lakewood Formation and San Pedro Formation) consist of inter‐layered pockets, layers and lenses of fine‐ and coarse‐grained materials as classified by the Unified Soil Classification System (USCS). For the purposes of its materials characterization, the Fernando Formation has generally been characterized as a soil; however, strength properties are provided for its sandstone layers and concretions.

For the purposes of this report, the sequence of layers, lenses and pockets of soil materials with differing grain size distributions are termed mixed soil conditions. Mixed‐soil conditions will be found within each geologic unit and also at transition zones where two (or more) geologic units are exposed in the excavation simultaneously. The heterogeneity of the ground (soil and rock) means that the engineering characteristics vary.

The geologic profiles (refer to Appendix A) present the subsurface in terms of:

1. Geologic units identifying:

a. Alluvial Soils – Younger and Older Alluvium

b. Lakewood Formation

c. San Pedro Formation

d. Fernando Formation.

2. Particle Size Distribution of Materials at station and shaft excavations and along the tunnel horizon (10 feet above tunnel crown to 10 feet below tunnel invert) identifying:

a. Predominantly Coarse‐ defined as soils with less than 50 percent passing the No. 200 Sieve and including soils classified as SC, SM, SP‐SC, SP‐SM, SW‐SC, SW‐SM, SP SW, GC‐GM, GC, GM, GP‐GM, GW‐GC, GW‐GM, GP, and GW.

b. Predominantly Fine‐Grained Soils – defined as soils with more than 50 percent passing the No. 200 Sieve and including soils classified as CH, CL, GL‐ML, MH, and ML.

c. Siltstone – defined as the siltstone and claystone (with sandstone interbeds and concretions) of the Fernando Formation.

3. Asphalt impacted soils.


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Geotechnical Baseline Report 4.0 – Engineering Characterization

The engineering characterization of the soils and rock bedrock engineering characterization is provided in Appendix BAppendix B for the tunnel reaches, tail track tunnels, and shaft and stations, respectively. Appendix B provides:

Frequency and thickness of layers and lenses of different soil types as classified by the USCS

Grain size distributions for materials sized less than three inches and fines content (percentage by weight passing No. 200 sieve). The grain size distribution curves include mean, mean plus one standard deviation, mean minus one standard deviation, mean plus two standard deviations, and mean minus two standard deviations to provide a basis for estimating the variability within ranges. It is to be anticipated that 95 percent of the particle size distributions of excavated material will be between the mean ± two times the standard deviation and this represents the gradation baselines for the materials that will be encountered during excavation.

Plasticity charts for the fine‐grained materials

The engineering parameters for the design of the temporary and permanent works are provided in Appendix C in terms of the ranges and baseline design values for the tunnel reaches, shaft and station locations.

4.2 Asphalt Characterization An assessment of the composition of the asphalt from samples taken from Borings G‐310, G‐311 (Metro, 2013f) and G‐312 (Metro, 2013c for boring locations and geologic logs) is provided in Figure 4‐1Figure 4‐1.




Figure 4-1: Distillation Product of Asphalt from the Asphalt Impacted Soils

Note: Results from the n-Paraffin Atmospheric Equivalent Boiling Point scale (Refer to Boduszynski et al, 1998)

The asphaltic material is highly viscous with a kinematic viscosity estimated to be approximately 100,000 centistokes at 65 degree Fahrenheit. The viscosity is temperature dependent and the viscosity/temperature relationship is shown in Figure 4‐2Figure 4‐2 and indicates that temperature changes in the range of those to be expected diurnally in excavations will result in changes in asphalt seepage inflow rates during the day.

For the purpose of classifying the asphalt impacted soils on boring logs, Table 4‐1 was developed for the project. It was based on visual examination of a suite of samples that were then tested to determine their actual asphalt content (by weight).

Table 4-1: Asphalt (Tar) Content Classification

Asphalt Content (by weight) Classification < 5% Slightly Infused Tar

5% - 15% Moderately Infused Tar >15% Saturated with Tar

These descriptions were subsequently applied to the samples and cores. Typically, the asphalt content is higher in the coarse grained materials where void spaces are larger and more easily penetrated by the


May 22, 2013 Page 4-4


viscous asphalt. Beds and lenses of asphalt impacted finer grained materials generally have lower asphalt contents.

Figure 4-2: Viscosity/Temperature Relationship

Asphalt content results are plotted in Figure 4‐3 for the full suite of tests performed along the alignment and for the tests on samples from the borings drilled for the Exploratory Shaft. For the complete set of data, the asphalt content (by weight) ranges as follows:tests, the results range up to about 29 percent (by weight), with an average value of 15 percent of asphalt (by weight). The asphalt content is dependent on the type of material being impacted. It averages about 18 percent in Fernando Formation, about 14 percent in silty sand and sand and about 9 percent in silt and clay samples.

Older Alluvium and Lakewood Formation 3.7 percent to 16.0 percent

San Pedro Formation 1.5 percent to 20.5 percent

Fernando Formation 6.4 percent to 29.5 percent

Of the samples tested, about ten percent were described as slightly infused (or saturated) with asphalt (“tar”), about 45 percent were moderately infused (or saturated), and about 45 percent were saturated with asphalt (“tar”), in accordance with the classification system presented in Table 4‐1.




Figure 4-3: Asphalt Content versus Depth

4.3 Ground and Groundwater Chemistry The Environmental Data Report (Metro 2013i) provides an assessment of the chemical constituents found in the ground and groundwater in Section 1. They include constituents found naturally in the ground and groundwater as well as man‐made contamination.

From the data, a suite of site environments that characterize chemicals and properties of concern have been developed for each station excavation location and tunnel reach. These chemicals of concern have an impact on the performance (durability, aging) of the materials used for construction (concrete, steel, rubber). The chemical of concern have been identified in the soil and groundwater in terms of:

Volatile Organic Compounds – VOCs are emitted as gases from many man‐made petroleum based products and are also found along the Section 1 alignment due to off‐gassing from the asphalt in the asphalt impacted soils.

Total Petroleum Hydrocarbons (TPH) – For the Section 1 alignment, naturally occurring asphalt impacted soils and groundwater are the main contributor to TPH concentrations. TPH organics encountered included: TPH‐gasoline range organics (GRO or TPH‐g); TPH‐diesel range organics (DRO or TPH‐d); and TPH‐oil range organics (ORO or TPH‐o). Each petroleum product is a complex mixture containing many different chemical compounds.

0

20

40

60

80

100

120

140

0% 5% 10% 15% 20% 25% 30% 35%

Dep

th below ground surface (feet)

Tar Content

Alignment/Stations Exploratory Shaft


May 22, 2013 Page 4-6


Soil corrosivity – A major factor determining soil corrosivity is electrical resistivity of soils.

Other Chemicals and Properties of Concern – Oil and grease, 1.4 Dioxane, hardness, pH, alkalinity, methane and hydrogen sulfide.

Based on the environmental data, three site environments were identified for chemicals of concern in the soils encountered and four site environments were identified for the chemicals and properties of concern in groundwater. These environments and their application to the different excavations are provided in Appendix D.

The Design‐Build Contractor should review the environmental data (Metro 2013i) to confirm that the site environments identified have included all the chemical constituents and properties that will affect the performance of the materials used for gas and water proofing (including membranes and gaskets) and develop process liquids that can be used to test the performance of these materials in accordance with Technical Requirements Section 07 10 00, Water and Gas Protection Systems. In addition, the Design‐Build Contractor should confirm that the concrete for the segmental tunnel liningconstruction materials used for the underground work is are durable in the site environments.

Corrosion Testing The analyses, conclusions and recommendations for the corrosion testing are documented in Metro 2011 (Appendix F of Metro, 2011), for the Wilshire/La Brea, Wilshire/Fairfax and Wilshire/La Cienega Stations, and for the tunnels within Section 1. Based on the analyses, the following assessment of the corrosiveness/aggressiveness of the soils was made:

Wilshire/La Brea Station – soil classified as severely corrosive to ferrous metals, aggressive to copper, very severe for sulfate attack on concrete, aggressive with respect to exposure of reinforcing steel to the migration of chloride, and aggressive with respect to exposure of concrete to acid attack

Wilshire/Fairfax Station – soil classified as severely corrosive to ferrous metals, aggressive to copper, very severe for sulfate attack on concrete, aggressive with respect to exposure of reinforcing steel to the migration of chloride, and aggressive with respect to exposure of concrete to acid attack

Wilshire/La Cienega Station – soil classified as severely corrosive to ferrous metals, aggressive to copper, moderate for sulfate attack on concrete and could be subject to microbial induced corrosion

Section 1 Tunnels – soil classified as severely corrosive to ferrous metals, aggressive to copper and severe for sulfate attack on concrete.

Specific studies were not performed for the Wilshire/Western shaft excavation and the tail track tunnels. The results for these must be based on data from the nearest investigations carried out in Section 1.

Stray Current Corrosion A preliminary in situ soil resistivity investigation program was performed to establish a corrosion control baseline with respect to the impact of the heavy rail system on DC stray currents. The investigation, the results, and the recommendations from the investigation are presented in Metro 2012f. It is the responsibility of the Design‐Build Contractor to review these findings and to develop its own field and laboratory investigation to determine the basis for selection of concrete and other materials used for the construction.




4.4 Gas Characterization Methane and hydrogen sulfide are the primary subsurface gases that will be encountered during tunneling and in excavations. These gases are found in gaseous form in the vadose zone and migrating upwards through the ground below the groundwater table. They are also found in solution in the groundwater and in the asphalt. Their presence is well recognized in Los Angeles. Methane and hydrogen sulfide are encountered in each of the formations through which the subway will pass, although they are typically found in higher concentrations within the San Pedro Formation. Significant concentrations of other hydrocarbon gases such as ethane, butane, propane and longer chain gaseous hydrocarbons were not detected in samples submitted for laboratory analysis.

Metro studied subsurface gas conditions for underground projects in the Mid Cities area of Los Angeles in the mid 1980’s1990’s. The studies found high levels of hydrogen sulfide south of Wilshire Boulevard along Crenshaw and Pico Boulevards. The highest gas readings occurred in the San Pedro Formation, generally in unsaturated zones capped by the less permeable Lakewood Formation and/or zones of semi‐perched groundwater. Hydrogen sulfide concentrations up to approximately 20,000 ppm were measured and extensive testing programs were undertaken to evaluate conditions.

Following the “Ross Dress‐For‐Less Fire” (Hamilton D.H and R. L. Meehan, 1992), the City of Los Angeles created a Methane Risk Zone Map in 1985 (subsequently updated) and adopted regulations for construction of buildings and other structures within the zone. The alignment with the exception of its eastern approximately 3,200 feet length passes through an area designated as a “Methane Zone” on the “Methane and Methane Buffer Zone” map published by the City of Los Angeles, Department of Public Works (2004). Between the Wilshire/La Brea Station and the Wilshire/La Cienega Station, the alignment also passes through areas designated as the “Potential Risk Zone”, “High Potential Risk Zone” and “Tar Pit Area”, on the 1984 Map prepared by City of Los Angeles, where risks from the methane are potentially higher (see Figure 4‐4Figure 4‐4).


May 22, 2013 Page 4-8


Figure 4-4: City of Los Angeles Methane and Methane Buffer Zone Map showing Section 1 of WSE

Relatively large volumes of methane are locally present within the upper portion of the San Pedro Formation. Over two million cubic feet of methane were extracted from a 4‐inch casing screened in the San Pedro Formation near the intersection of Pico and San Vicente Boulevards in approximately 1996 without affecting the gas concentrations or pressures.

For the WSE Project, gas monitoring studies have been carried out to measure 1) Gases dissolved in the groundwater, 2) Gases found in the vapor phase in the ground along the alignment, and 3) Gas pressures. A summary of the gas results (over the period from 2009 to May 2012) along the alignment is presented in Metro 2013 a‐h for stations, shaft and tunnel reaches. Table 4‐2Table 4‐2 identifies the tables in the reports where results of the gas monitoring are presented for the different excavation locations and tunnel reaches can be found.

When totaled up, the gas concentrations presented in the reports identified in Table 4‐2Table 4‐2 do not generally total 100 percent as all gases are not accounted for. Since contamination by air occurs, nitrogen, carbon dioxide and argon likely account for the balance of the gas that is “missing” in the




monitoring result totals. Appendix E provides a discussion of the impacts of air contamination on gas readings.

The monitoring wells installed during the ACE and PE/APE phases, and other historic wells, are planned to be continued to be monitored periodically prior to the time of construction.

Table 4-2: Gas Results Summary

Location Geotechnical Data

Report Gas Probes & Standpipes

in Monitoring Wells

Gas Results as reported in GDRs

Tables Plates

Wilshire/Western Shaft Metro, 2013a No gas monitoring - -

Tunnel Reach 1 Metro, 2013e Table 4-2 Tables 4-3 through 4-5 Plate 3

Wilshire/La Brea Station Metro, 2013b Table 4-2 Tables 4-3 through 4-5 Plate 3

Tunnel Reach 2 Metro, 2013f Table 4-2 Tables 4-3 through 4-6 Plate 3

Wilshire/Fairfax Station Metro, 2013c Table 3-3 Tables 3-4 through 3-12 Plate 3

Tunnel Reach 3 Metro, 2013g Table 4-2 Tables 4-3 through 4-7 Plate 3

Wilshire/La Cienega Station Metro, 2013d Table 3-2 Tables 3-3 through 3-7 Plate 3

Tail Track tunnels Metro, 2013h Table 4-2 Tables 4-3 through 4-4 Plate 3

Along the alignment extending from the intersection of Wilshire Boulevard and Highland South Dunsmuir Avenue to the end of the tail track tunnel at the intersection of Wilshire Boulevard and Stanley Drive and including the station excavations at Wilshire/Fairfax and Wilshire/La Cienega, a zone of elevated gas conditions has been identified. For the purposes of this GBR, “elevated” has been defined as locations where gas monitoring readings have shown:

Methane levels above five percent or

Hydrogen Sulfide levels above five ppm

The gas pressure data indicate that the subsurface gases are under pressure below the groundwater table. The highest gas pressures measured in the soil in the gas probes and standpipes generally do not exceed the hydrostatic head of the perched water zones above them. However, exceptions were measured in the upper portion of the San Pedro Formation at M‐106 and M‐108, where persistent gas pressure of 2.8 psi and 3.6 psi, respectively above the hydrostatic head were measured. Where artesian gas pressures have been measured, they are the result of gas and groundwater trapped beneath highly relatively impermeable layers.

Potential off‐gassing of methane and hydrogen sulfide from groundwater can release large volumes of gas. The volume of gas dissolved in the groundwater increases with pressure; hence, the excavation of the soils will result in the dissolved gases being released as the pressure on the groundwater reduces. The amount of gas dissolved in groundwater under pressure must be taken into account when evaluating gas volumes released from the ground and groundwater during excavation.

Figure 4‐5 and Figure 4‐6 provide a basis for estimating the volume of methane and hydrogen sulfide that will off‐gas from the excavated material at depth. The estimates are based on:


May 22, 2013 Page 4-10


Baseline Upper estimates of methane and hydrogen sulfide concentrations (see Sections 6, 7 and 8)

Dissolved gas concentrations in equilibrium in accordance with Henry’s Lawthe groundwater and asphalt

Unsaturated soils, 60 percent saturated with groundwater

Soil and bedrock porosities of:

– Non Asphalt Impacted Soils – 38 percent

– Asphalt Impacted Soils – 39 percent

– Fernando Formation – 48 percent

Groundwater table 10 feet below ground surface

Gases at hydrostatic pressure below groundwater table




Figure 4-5: Potential Methane Off Gas Volume


May 22, 2013 Page 4-12


Figure 4-6: Potential Hydrogen Sulfide Off Gas Volume


5.0- Man Made Features of Construction SignificanceMan Made Features of Construction Significance


5.0 MAN MADE FEATURES OF CONSTRUCTION SIGNIFICANCE

This section identifies the manmade features (including the regulation of environmentally impacted soils) that will affect the construction of the tunnels, mined excavations, cut‐and‐cover sections, and station excavations.

5.1 Structures along the Alignment The corridor lies within two jurisdictions within the County of Los Angeles – the City of Los Angeles and the City of Beverly Hills. Within 120 feet of the centerline of the rail tracks, the tunnels pass by 213 buildings of which 20 buildings are ten stories or more and 89 are between three and nine stories. The buildings are identified on the project definition drawings as is the historic or historic eligibility status.

The types of structures along the alignment are primarily commercial and residential buildings. The commercial buildings are mainly offices and retail stores consisting predominantly of older one‐ and two‐story masonry and concrete structures with a few light one‐story steel frame structures. Available information on the buildings collected by Metro is available on requestprovided in reference documents. Additional information may be available from the City of Los Angeles and City of Beverly Hills Building Departments.

No structures are directly above the tunnels. When tunneling specifications are met, none of the buildings are anticipated to experience settlements that exceed the allowable settlement estimated from tunneling. The Project Definition Drawings identify structures at station locations that because of their historic status (or eligibility) should be given particular consideration to ensure that they are protected. It is the responsibility of the Design‐Builder Contractor to evaluate the impact of tunneling and station, crossover and cross passage excavation on the structures along the alignment and to develop building protection measures to assure that the buildings are not damaged by the Metro construction.

Other construction features than can impact Metro construction include:

Soldier Piles beneath Sidewalks – At station excavation locations, soldier piles remaining in place should be expected wherever building basements have been excavated. They are likely located within a corridor about 3 to 4 feet from the property line beneath the sidewalk. The Design‐Build Contractor should investigate and place its soldier piles to avoid any that remain in place.

Tiebacks ‐ A total of 27 structures along the Section 1 alignment were identified as having had below grade walls temporarily supported during construction with tiebacks. Of these, the tiebacks for seven eight buildings lie within the tunnel and station construction works and tiebacks for theshaft at Wilshire/Western Station are within the shaft excavation at Wilshire/Western. These structures are identified in Table 5‐1 and indicated on the drawings.


May 22, 2013 Page 5-2

Geotechnical Baseline Report 5.0 – Man Made Features of Construction Significance

Table 5-1: Tiebacks expected to Intrude into Station Excavations and Tail Track Tunnels

Location Address of Building where Tiebacks Intrude

into Station Excavation Estimated No. of

Tiebacks to be Removed

Wilshire/Western Shaft Wilshire/Western Station 8

Wilshire/La Brea Station 5115 Wilshire Blvd 10

5200 Wilshire Blvd 40

Wilshire/Fairfax Station 6100 Wilshire Blvd 70

Wilshire/La Cienega Station 8350 Wilshire Boulevard 40

8383 Wilshire Boulevard 100

8484 Wilshire Boulevard 120

Tail Track Tunnels at Wilshire/La Cienega Station 8536 Wilshire Boulevard 20

Tieback anchors may extend into the proposed shaft excavation at Wilshire/Western. The Design‐Build Contractor should investigate the shoring system used during construction of the station to determine whether tiebacks will be encountered or not.

Tiebacks from six of the buildings will be encountered at station excavations.

One building has tieback anchorages that impact the tail track tunnels west of Wilshire/La Cienega Station. These tiebacks have been partially removed but 2 inch thick steel plates (some 8‐inch square and others 12‐inch square and a portion of the steel rods) remain in the ground and are expected to be above the tunnel envelope. Metro is performing additional investigations to locate the locations of these tiebacks. The results of the investigations will be provided once they become available. If necessary, given the proximity of these tiebacks to the tunnels, the Design‐Build Contractor will be required to develop means to remove them.

Buildings for Demolition – Five buildings will be demolished to provide work sites and locations for shaft and station entrance excavations. The buildings are listed in Table 5‐2 with summary information regarding their below grade foundation structures. The Design‐Build Contractor should review building plans to obtain detailed information on the foundations that need to be removed and environmental reports prepared by Metro regarding environmental considerations (i.e., lead, asbestos) that must be dealt with during building demolition.

Table 5-2: Foundations for Buildings Demolished as Part of Contract

Location Address Foundations

Wilshire/Western Shaft 3839 Wilshire Blvd Slab on grade

Wilshire/La Brea Station 5301 Wilshire Blvd Shallow wall footings

Wilshire/Fairfax Station 6030 Wilshire Blvd Shallow spread footings

Wilshire/Fairfax Station 6018 Wilshire Blvd Shallow wall footings

Wilshire/La Cienega Station 8471 Wilshire Blvd Piles up to 31 feet in length with tie beams between piles.




5.2 Utilities Numerous utilities including water, telephone, gas, electrical and telecommunication lines, pipelines, storm drains, and sewers are located within the street rights‐of‐way along the proposed underground segment alignment. Known locations, types and configurations of the utilities along the alignment are presented baselined in the Project Definition Drawings.

Once utilities requiring protection have been identified in accordance with the Technical Requirements Section 31 71 19, Excavation by Tunnel Boring Machine, a program for utility monitoring and protection is to be designed and implemented to meet requirements. Coordination with utility owners shall be carried out in accordance with Technical Requirement 01 31 31.

5.3 Abandoned Oil Wells and Facilities No abandoned oil wells and facilities have been physically found within the Section 1 tunnel alignment but seven wells have been identified from DOGGR records as close to the alignment. They are identified in the plan views in Appendix A and a brief history is given in Table 5‐3. Additional information is provided in GDRs. Given the reported accuracy of the wells on DOGGR maps (to within 200 feet), each well is shown centered on a 200 foot radius zone and should be anticipated to be located anywhere within the zone. All seven well locations must be investigated to establish which are within the construction work. Investigations should continue until all sites are fully explored even if abandoned wells are identified. For Section 1, it is to be assumed that one abandoned well (out of the seven identified) in the excavations or tunnels will be found and must be dealt with in accordance with the General Requirements Section 01 35 43, Environmental Procedures for Contaminated and Hazardous Materials.

Table 5-3: Oil Wells along Alignment

Well ID Potential Encroachment

Chevron #03715159 Well drilled in 1907 and abandoned in 1908

Chevron #03706478 (Tower Corehole #1) Well abandoned in 1965

Chevron #0371544 Well abandoned in 1913

Chevron #03714970 ( Salt Lake 10) Well drilled in 1907 and deepened in 1911. Abandonment test performed in 1996. Status – Idle.

Chevron #03701151 Well drilled and abandoned in 1964. Well plugged with cement below 371 feet and filled with ready-mix concrete above a depth of 371 feet. Steel plate 5 feet bgs. No gas

Chevron #03720045 Well drilled and abandoned in 1967. Hole plugged with cement

Chevron #03706346 Well plugged. Little information on well depth

The “Salt Lake” 10 well is indicated to be in the northwest quadrant of the intersection of Wilshire Boulevard and Fairfax Avenue. Well construction records available for well “Salt Lake” 10 indicate that it was built in 1907, but there is no information regarding its abandonment. It is recorded as idle – indicating it is currently inactive but not decommissioned.

Based on the results of a geophysical survey performed at the intersection of Wilshire Boulevard and Fairfax Avenue (refer to Section 4‐2), no definitive evidence of an abandoned oil well has been found. However, interference from metal objects and buildings in the vicinity could have obscured any


May 22, 2013 Page 5-4


indication of the well. As the locations of oil wells on DOGGR maps are not accurately shown, the presence of “Salt Lake” 10 within the alignment or the station excavation at Wilshire/Fairfax cannot be discounted.

In the areas where abandoned oil wells could potentially be encountered, probe holes ahead of the face and geophysical surveys to detect obstructions will be required. If an abandoned oil well is detected underground ahead of the face, an evaluation of its condition and its abandonment must be carried out in accordance with appropriate regulations.

Should any abandoned wells be encountered, it must be assumed that they contain large quantities of water, drilling mud, hydrocarbons under pressure, methane, and/or hydrogen sulfide and other toxic/explosive gases. Wells may be constructed with steel or timber casings. Wells abandoned since 1942 are expected to be grouted. However, wells abandoned prior to 1942 were typically filled with mud and sealed at the surface with a steel cap. Undocumented abandoned oil wells have been found during previous tunnel and shaft excavations in the Los Angeles area and have been successfully abandoned (Keller and Crow, 2004). For Section 1, it is to be assumed that one abandoned well (out of the seven identified) in the excavations or tunnels and must be dealt with in accordance with the General Requirements Section 01 35 43, Environmental Procedures for Contaminated and Hazardous Materials. All seven well locations must be investigated to establish which are within the construction work. Investigations should continue until all sites are fully explored even if abandoned wells are identified.

5.4 Ground and Groundwater Contamination For the purpose of the GBR, “environmentally impacted” refers to any soil, rock or groundwater containing chemicals or constituents of concern that, if excavated, could require special handling and disposal arrangements. Chemicals or constituents of concern are in accordance with Resource Conservation and Recovery Act (RCRA) under Federal Regulations (RCRA 40 CFR, Section 261) or per California Regulations (Title 22 CCR, Division 4.5, Chapter 11, Article 3, Section 66261).

The investigations of environmentally impacted locations and the results obtained are presented in the EDR Environmental Data Report (Metro 2013i). Both the naturally asphalt impacted soils and bedrock, and the source locations for man‐made contamination are identified. The Design‐Builder Contractor is required to satisfy itself as to any special handling, transportation and disposal requirements and the appropriate locations for disposal that meet applicable regulations. Although an effort has been made to identify all areas of environmentally impacted materials (including asphalt impacted soils, groundwater and man‐made contamination) that can impact construction activities, other areas may exist. Therefore, the Contract also contains requirements for monitoring for hazardous and contaminated materials and for transportation and disposal.

The total petroleum hydrocarbons (TPH) content of the asphalt impacted soil, if excavated, would beare

at levels that classify them as “environmentally impacted” but not RCRA hazardous (not a Federal hazardous waste) in accordance with RCRA Federal regulations; but based on California Regulations (Title 22 CCR 66261) they would be California hazardous (Non‐RCRA or California only waste). However, to de‐classify the asphalt impacted soil from being a California only waste (Non‐RCRA waste), samples were analyzed and passed the Acute Aquatic Toxicity Test [(Bioassay Fish Kill Test‐Title 22 CCR 66261.24(a)(6)], and based on this assessment, the excavated soils could be disposed of at a Class II




landfill or could be used at a recycling facility producing asphalt for commercial use. The Design‐Builder is required to satisfy itself as to any special handling, transportation and disposal requirements and the appropriate locations for disposal that meet applicable regulations.

Man‐made contamination associated with former industrial and commercial land use includes petroleum, hydrocarbons, volatile organic compounds, semi‐volatile organic compounds, and metals. The locations of environmentally impacted soils from these sources along the alignment are provided in Table 5‐4. Of the sites investigated, there were no locations at tunnel depths or at station locations where contamination classified as hazardous was identified.

It is estimated that the excavations for the tunnels and cross passages between South Dunsmuir Avenue and South Crescent Heights Boulevard and at the Wilshire/Fairfax Station site where asphalt impacted soils will be encountered will produce 350,000 (unbulked) cubic yards that require special handling, transportation and disposal. This is based on the environmental investigations and the excavations for the structures shown on the project definition drawings. No contamination has been identified as RCRA hazardous (requiring special handling and disposal at a Class I landfill). Specific measures in accordance with the General Requirements Section 01 35 43, Environmental Procedures for Contaminated and Hazardous Materials, will be required to handle contaminated and hazardous materials where they are encountered.

Although an effort has been made to identify all areas of environmentally impacted materials (including asphalt impacted soils, groundwater and man‐made contamination) that can impact construction activities, other areas may exist. Therefore, the Contract also contains requirements for monitoring for hazardous and contaminated materials and a provisional sum for handling, transportation and disposal.

The Contractor will be required to carry out environmental investigations as part of an NPDES permit application package if dewatering requires discharge into the municipal storm drain system. To assist in establishing the treatment and disposal requirements for groundwater, Table 3‐8 of Metro, 2013i provides a comparison of the test results obtained with the requirements for NPDES permit and discharge requirements for Ballona Creek and Table 3‐9 of Metro, 2013i provides a comparison with the discharge requirements for the City of Los Angeles, Bureau of Sanitation.


May 22, 2013 Page 5-6


Table 5-4: Summary of Boring Locations and Suspect Sources for Hazardous Materials

Location Boring No. Suspect Source(s)

Tunnel Reach 1

E-101 Spills, Leaks, Investigations and Cleanups [SLIC] case (former dry cleaners at 3807 Wilshire)

E-102 Closed Leaking Underground Storage Tank (LUST)case (3855 Wilshire)

E-103 E-103A Closed LUST case (3875 Wilshire)

E-104 Existing dry cleaners (4001 Wilshire) and closed LUST (4006 Wilshire)

E-105 Former service stations on SW Corner and SE Corner of intersection. Vent shaft location

E-106 E-106A

SLIC case (former service station at 5020 Wilshire) and SLIC case (dry cleaners at 5034 Wilshire)

E-107 E-107A SLIC case (former service station at 5020 Wilshire) and SLIC case (dry cleaners at 5034 Wilshire)

Wilshire/La Brea Station

E-108 E-108A E-108B

LUST case (former auto dealership at 5151 Wilshire)

E-109 E-109A SLIC case (5220 Wilshire)

E-110 E-110A Former services stations at intersection and SLIC case (5220 Wilshire)

E-111 Former service stations/dry cleaners (5347-5351 Wilshire)

Tunnel Reach 2

E-112 Petroleum/Tar Deposits

E-113 Petroleum/Tar Deposits

E-114 E-114A E-114B

Petroleum/Tar Deposits

Wilshire/Fairfax Station

E-115 E-115A E-115B

Former service station property and current Underground Storage Tank (UST) site at 6100 Wilshire Boulevard.

E-116 Naturally occurring tar sands and/or former (idle) oil production well (adjacent to 6111 Wilshire)

Tunnel Reach 3

E-116A

E-117 E-117A

Former auto gas & oil/ car wash

E-118 E-118A E-118B

Existing dry cleaning facility (6250 Wilshire)

E-119 Former oil production well (plugged)

E-120

Former LUST site (8383 Wilshire), cleaners, hazardous materials spill (Wilshire/San Vicente) and background

Wilshire/La Cienega Station

E-120A

E-120B

E-121 E-121A E-121B

Auto sales-repair/gas

E-122 Former gasoline stations

E-122A Former gasoline stations (8483 Wilshire)

Tail Track Tunnel E-123 Closed LUST with residual groundwater contamination (8567 Wilshire)


6.0- TBM Tunnels


6.0 TBM TUNNELS

Tunnel construction will be in water‐bearing soft ground. Because tunneling will take place through built‐up areas, control of ground losses and surface settlement to minimize damage to structures, buried utilities and streets along the alignment is a primary consideration for the selection of the tunneling method.

For the baseline for the Section 1 tunnels:, Geologic profiles for the alignment isare presented in Appendix A and the .Eengineering characterization of soils and rock encountered is given in Appendix B.

Baseline values for engineering properties to be used for design within each reach are given in Appendix C.

Baseline chemical constituents within the ground and groundwater for which structural materials must be resistant to are presented in Appendix D.

The Design‐Build Contractor is responsible for developing the engineering parameters used for design.

In the past, Los Angeles’ geology has presented challenges to tunneling due to the seismic conditions and the presence of subsurface methane and hydrogen sulfide gases. As a result, Metro Rail projects and other tunneling projects have studied the conditions and developed approaches to the design and construction of tunnels in the area. A summary of studies and tunnel construction experience from previous Los Angeles tunneling projects and other pertinent projects is provided in Appendix F.

6.1 Tunnel Reach 1 - Wilshire/Western Access Shaft to Wilshire/La Brea Station Tunnel Reach 1 from the Wilshire/Western Retrieval Shaft to Wilshire/La Brea Station is approximately 1.82 miles long. Within the reach, the tunnel invert varies from 55 to 121 120 feet below the ground surface. The geologic units encountered at the tunnel horizon consist of:

The San Pedro Formation consisting primarily of layers and lenses of coarse‐grained soils comprising dense to very dense sands and silty sands (SC, SM, SP‐SM, SW‐SM, SP, SW and GM) interbedded with layers and lenses of fine‐grained soils comprising silts and clays (CH, CL, CL‐ML, MH and ML).

Fernando Formation consisting of very weak to weak cemented siltstone and claystone with occasional interbeds of sandstone layers and calcium carbonate cemented concretions. The hard layers and concretions are anticipated to be up to five percent by volume of the Fernando Formation excavated.

The tunnels transition from the San Pedro Formation into the Fernando Formation over a distance of approximately 3,800 feet and transitions from the Fernando Formation back into the San Pedro Formation over a distance of approximately 400 feet. Not only in the transition zones but also within a full face of San Pedro Formation, the interbedding between coarse and fine‐ grained layers will produce mixed soil conditions.

Abandoned Oil Wells ‐ An abandoned oil well (Chevron #03706346) is mapped at a distance of about 70 feet north of the tunnel near the middle of the reach. In addition, there are two oil wells (Chevron #03701151 and Chevron #03720045) that could beare either within Tunnel Reach 1 or the Wilshire/La Brea Station excavation. The exact locations of these wells are not known but the vicinities of their


May 22, 2013 Page 6-2

Geotechnical Baseline Report 6.0 – TBM Tunnels

locations are shown in Appendix A. Refer to Section 5.3, Abandoned Oil Wells and facilities for further details regarding oil well obstructions and their abandonment

6.1.1 Groundwater

The groundwater level shown on the plate for geologic profile for Tunnel Reach 1 represents the historic high water levels. For baseline purposes, groundwater level during construction is expected to remain within a range from 0 feet above to 10 feet below the groundwater level shown on the geologic profile.

6.1.2 Gases

The entire length of Tunnel Reach 1 will be classified as “gassy” by Cal/OSHA.

Conditions within the reach will vary with location. Gases will be found in the groundwater and in the San Pedro Formation, primarily in the void space and will also be encountered within fractures within the Fernando Formation. It is anticipated that the following represent the maximum gas conditions within the groundwater and within the pore spaces in the vadose zone for the reach:

Methane levels at two percent, and/ or

Hydrogen Sulfide levels at two ppm

Gases beneath the groundwater table will be under pressure equivalent to the hydrostatic head.

6.2 Tunnel Reach 2 - Wilshire/La Brea Station to Wilshire/Fairfax Station Tunnel Reach 2 of Section 1 of the WSE, from the Wilshire/La Brea Station to Wilshire/Fairfax Station is approximately 0.84 miles long. Within the reach, the depth to tunnel invert varies from 65 to 120 feet below ground surface. The geologic units encountered at the tunnel horizon consist of:

The San Pedro Formation consisting primarily of layers and lenses of dense to very dense sands, clayey sands and silty sands ( SC, SM, SP‐SM,SW‐SM, SP and SW) with occasional gravel (GM, GP) layers and interbedded with layers and lenses of silts and clayey silts (CL‐ML and ML).

Fernando Formation consists of very weak to weak siltstone and claystone with an unconfined compressive strength up to 135 psi with occasional interbeds of sandstone and harder calcium carbonate cemented siltstone layers. A full face of Fernando Formation will be encountered over approximately 43 percent of the tunnel alignment. It is estimated that the hard layers of sandstone interbeds and calcium carbonated cemented siltstone layers will be less than three feet thick and be less than five percent of the Fernando Formation encountered. The sandstone layers and concretions will have strengths up to 14,500 psi and splitting strengths up to 1,700 psi.

Between South Dunsmuir Avenue and the Wilshire/Fairfax Station at the tunnel zone, the soils are impacted with asphalt. The asphalt content of the soils will range from 2 to 30 percent by weight with an average value ofaverage 15 percent by weight in the San Pedro Formation and average 18 percent by weight in the Fernando Formation.

There are three transition zones, where the tunnels will pass either into or out of the coarse‐grained soils of the San Pedro Formation and the siltstone of the Fernando Formation. The San Pedro/Fernando transition zones represent 16 percent of the length of Reach 2. Not only in the transition zones but also


6.0- TBM Tunnels


within a full face of San Pedro Formation, the interbedding between coarse and fine‐ grained layers will produce mixed soil conditions.

Abandoned Oil Wells ‐ According to maps published by the California Division of Oil, Gas, and Geothermal Resources (DOGGR, 2010), the Reach 2 tunnel alignment is located within the boundary of the South Salt Lake oil field but there are no oil wells mapped within 200 feet of the alignment.

6.2.1 Groundwater

The groundwater levels shown on the geologic profiles represent the historic high water levels. The groundwater table levels during construction are expected to remain within a range from 0 feet above to 10 feet below the groundwater level shown.

6.2.2 Gases


Conditions within the zone will vary depending on location. . Gases will be found in the San Pedro Formation, primarily in the void space and will also be encountered within fractures within the Fernando Formationformations and in the groundwater. A zone of “elevated” gas conditions extending from South Dunsmuir Avenue Wilshire/La Brea Station westwards throughout Reach 2 has been identified. It is anticipated that the following represent the maximum gas conditions within the groundwater and within the pore spaces in the vadose zone for the reach:

Methane levels at 100 percent, and/or

Hydrogen Sulfide levels at 700 ppm


6.3 Tunnel Reach 3 - Wilshire/Fairfax Station to Wilshire/La Cienega Station Tunnel Reach 3 from Wilshire/Fairfax Station to Wilshire/La Cienega Station is approximately 0.62 miles long. Within this reach, the depth to tunnel invert varies from 60 to 100 feet below ground surface. The geologic units encountered at the tunnel horizon consist of:

The coarse‐grained soils of the San Pedro Formation consist primarily of layers and lenses of dense to very dense sands, clayey sands and silty sands (SC, SM, SP‐SM, and SP) with interbedded layers and lenses of silts and clays (CH, CL, MH and ML). The tunnels are within these interbedded deposits for the entire length of Reach 3.

At the tunnel horizon between Wilshire/Fairfax Station and South Crescent Heights Boulevard, the soils will be impacted with asphalt. The asphalt content of the soils will range from 4 to 18.5 percent by weight with an average content of 9.515 percent by weight.

Abandoned Oil Wells ‐ According to maps published by the California Division of Oil, Gas, and Geothermal Resources (DOGGR, 2010), the tunnel alignment in Reach 3 is located within the boundary of the South Salt Lake oil field. Four abandoned oil wells (Chevron #03714970, Chevron #03715144, Chevron #03706478, and Chevron #03715159) are identified within the tunnel reach (with the possible location of one well within tunnel reach or the Wilshire/Fairfax Station excavation). A geophysical survey was performed at the intersection of Wilshire Boulevard and Fairfax Avenue to find “Salt Lake”


May 22, 2013 Page 6-4


10 well. No definitive evidence was obtained regarding the exact location of any of these wells but the vicinities within which they are located are shown in Appendix A. Refer to Section 5.3, Abandoned Oil Wells and facilities for further details regarding oil well obstructions and their abandonment.

6.3.1 Groundwater


6.3.2 Gases


Conditions within the zone will vary depending on location. A zone of “elevated” gas conditions extending from Wilshire/Fairfax Station westwards throughout Reach 3 has been identified. It is anticipated that the following represent the maximum gas conditions within the groundwater and within the pore spaces in the vadose zone for the reach:


Hydrogen Sulfide levels at 10,000 ppm


6.4 Tail Tracks Tunnel Reach - West of La Cienega Station Tail track tunnels approximately 800 feet long are required west of Wilshire/La Cienega Station. Within this reach, the depth to tunnel invert varies from 60 to 100 feet below ground surface.

The geologic units encountered consist of:

San Pedro Formation consisting primarily of layers and lenses s of stiff to hard sandy silts and clays (CL, CH and CL‐MH) and stiff to very stiff elastic silt (MH) with sand and carbonate concretions interbedded with dense to very dense sands, clayey sand and silty sand (SC, SC‐SM, SM, SP‐SM, SP‐SC, SW‐SM and SP). The tunnels are within these interbedded deposits for the entire length of the Tail Track Tunnels.

As indicated in Section 5‐1 (and on the Project Definition Drawings), the tunnels will pass by the building at 8536 Wilshire Boulevard at a depth at which the steel and concrete remnants from tiebacks used to temporarily support the excavation for the building basement are within the tunnel envelope. These tiebacks have been partially removed but 2 inch thick steel plates (some 8‐inch square and others 12‐inch square and a portion of the steel rods) remain in the ground and are expected to be within the tunnel envelope. close to the tunnels. The Design‐Build Contractor must develop and implement a plan to verify that the tiebacks will not impact the tunnels and if they do, remove the steel either prior to start of tunneling or from ahead of the face during the TBM drives. The plan should must take into account the gassy nature of the ground.


6.0- TBM Tunnels


6.4.1 Groundwater


6.4.2 Gases

The entire length of the tail track tunnels will be classified as “gassy” by Cal/OSHA.

The tail track tunnels remain within the zone of “elevated” gas conditions that extends from Wilshire/Fairfax Station. It is anticipated that the following represent the maximum gas conditions within the groundwater and within the pore spaces in the vadose zone for the reach:




6.5 TBM Excavation

6.5.1 Closed Face TBMs

The use of pressurized closed‐face Tunnel Boring Machines (TBMs) – either earth pressure balance or slurry shield TBMs – is required for tunneling. Without the application of a positive pressure to the face, the soils will run, flow, and ravel. When operated effectively, closed‐face TBMs, apply a positive pressure to the tunnel face at all times, thus reducing the risk of soil inflows and groundwater flooding the tunnel, and minimizing ground losses that can result in surface settlements in the soft ground conditions to be encountered in the deposits found in the Los Angeles Basin.

A further consideration for using closed‐face TBMs is the presence of methane and hydrogen sulfide found within the ground and groundwater. Closed Face TBMs provide the isolation of the tunnel face from the working environment in the tunnel. This is beneficial as it reduces the air in the tunnel from being contaminated with methane and hydrogen sulfide from the ground or groundwater and provides the opportunity for off gassing from excavated spoil and groundwater to be controlled. For the face pressure to be effective in controlling gases, it must be sufficient to counteract the gas pressure. It is anticipated that a face pressure at least equivalent to the hydrostatic head must be applied at all times including when excavating through the Fernando Formation. Within this fthe Fernando Formation the presence of groundwater and gas in fractures must be counteracted although the face pressure may not be needed to stabilize the face.

For the positive face pressure to be effective in controlling ground loss, it must be sufficient to mobilize the internal friction within the soil mass and thereby support the excavated face and prevent ground and groundwater movement towards the face. It is anticipated that a pressure must be applied to the face not less than the combined active earth pressure (Ka) and water pressure. Face pressures should be maintained between the active earth pressure and at‐rest earth pressure (Ko) in cohesionless soils to control ground movement and ground relaxation about the tunnel. Fluctuations in the pressure applied to the face will occur as the ground conditions and the composition of the spoil or fluid within the working chamber of the TBM changes. Therefore, continuous monitoring and careful control of the


May 22, 2013 Page 6-6


pressure applied to the face is required throughout tunnel excavation to assure that ground loss through the face is minimized.

For an EPB TBM, proper conditioning of the spoil within the excavation chamber is required so that it will act as a viscous fluid supporting the face. Conditioning that produces low support pressures can result in runs, caving and progressive instability of coarse‐grained material in the face and should be avoided. High support pressures can result in excessive torque requirements for the cutting wheel and arching of the muck at the entrance to the screw conveyor that inhibits discharge and should also be avoided. Fluctuations in the support pressure applied to the face as a result of changing ground conditions must be expected and planned for.

For a slurry face TBM, the face pressure must be maintained by the use of bentonite slurry. It will be necessary to vary the density and constituents of the slurry and take into account fluctuations in the soils being excavated and in groundwater conditions.

Additives and slurries introduced into the EPB or Slurry Shield TBM operations to condition the spoil to support the face or handle it, must be effective in the full range of ground and groundwater chemistries encountered and characterized in Appendix D.

6.5.2 TBM Selection

Among the factors determining a machine’s selection and its performance are tunnel size, depth of overburden, range of the grain size distributions being excavated, clay mineralogy, natural moisture content, and hydraulic conductivity, strength, and groundwater conditions. The soil and groundwater parameters related to these factors are provided in the contract documents and in this report.

TBM selection will be a trade‐off between technologies that promote efficient tunnel advance in the sands, silty sands, clayey silts, silts and siltstone and those that better separate the tunnel ventilation system from the methane and hydrogen sulfide gases off‐gassing emanating from excavated materials.

Generally, an EPB TBM is likely to be more effective excavating through fine sands, silty sands, silts clays and siltstone. Once the excavated material has passed through the working chamber of the TBM and the screw conveyor, methane and hydrogen sulfide will be released into the tunnel atmosphere and must be handled by the ventilation system to meet applicable regulations with regard to safe working conditions.

A slurry shield TBM must consider the process for separating the spoils from the slurry when excavating through fine sands, silty sands, silts clays and siltstone. In these soils, the slurry shield TBM has the advantage that the excavated materials are transported in a slurry mix to the surface by a piping system. This system, being closed, can help keep methane and hydrogen sulfide from the spoil material separate from the tunnel ventilation. At the surface, the gases can be discharged from the piping system and processed in accordance with applicable regulations away from the tunnel ventilation.

Other factors including excavation advance rates, cutter head torque, wear (cutting system and muck removal system), utilization, and other performance parameters have not been evaluated for this report and require evaluation by the contractor. An appropriately designed and operated TBM should also consider the following factors:


6.0- TBM Tunnels


Openness of the cutter head to ensure the transfer of support pressure to the tunnel face and to facilitate the unimpeded flow of excavated material into the working chamber.

Use of additives including bentonite and conditioners to condition the excavated material to support the face, increase the range of soil and groundwater conditions in which machines operate, reduce torque and power consumption and facilitate handling and removal of spoil from the tunnel

The size, quantity and composition of the ingested soils

Flexibility of system to adapt to conditions without major re‐tooling or costly delays

Grouting of the annular tail shield gap as the TBM advances to provide a backfill that gives immediate support for the segment ring preventing ring distortion and ground movements

Synchronization of the excavation advance with the grout volumes and the rate of muck removal

Filling and pressurization of the overcut around the shield

6.5.36.5.2 Soil Abrasion

Excavation and handling of the sands, gravels and cobbles will abrade and wear the cutter head, the excavation chamber and the muck removal system. The Contractor and machine manufacturer must include provisions for these effects in the design, selection and operation of equipment.

The relative abrasiveness of the materials encountered was evaluated using the Norwegian University of Science and Technology (NTNU) test procedure to determine Soil Abrasion Testing (SAT) values. Guidance to the soil abrasiveness can be obtained using the classification developed by the University of Texas shown in Table 6‐1.

Table 6-1: Classification of Abrasiveness of Soil and Rock

Abrasivity Category SAT Value

Extremely Low < 1

Very Low 2 – 3

Low 4 – 12

Medium 13 – 25

High 26 – 35

Very High 36 – 44

Extremely High > 45

The results of the tests (refer to Appendix B of Metro, 2013a and Appendices G of Metro 2013 b‐h) are summarized in Table 6‐2 and classified by formation and soil type (fine and coarse‐grained). Based on the results summary, high to very high abrasive soils are to be anticipated in the coarse‐grained Lakewood and San Pedro Formations.

Very hard to extremely hard cobbles in the alluvium, Lakewood and San Pedro and the hard sandstone layers and concretions in the Fernando Formation will result in abrasion, wear, and breakage of tools on the cutting head of TBMs.


May 22, 2013 Page 6-8


Table 6-2: Abrasion Test Results by Geologic Formations

Geologic Formation Soil Type

Data Points Median

Standard Deviation Minimum Maximum

Abrasivity Category

Older Alluvium (Qalo)

Fine-Grained 9 4.0 2.7 1.6 8.2 Very Low to Low

Coarse-Grained 8 10.3 3.7 4.5 16.0 Low to Medium

Lakewood (Qlw) Fine-Grained 1 4.0 * 4.0 4.0 Low

Coarse-Grained 3 25.5 1.2 25.5 27.5 Medium to High

San Pedro (Qsp) Fine-Grained ** ** ** ** **

Coarse-Grained 18 24.5 9.5 5.5 38.0 Low to Very High

Fernando (Tf) Fine-Grained 7 2.0 2.0 1.5 6.5 Very Low to Low

Coarse-Grained ** ** ** ** **

* Only one data point, **No test data

6.5.46.5.3 Soil Stickiness

The cohesive nature of the excavated fine‐grained materials is expected to impact spoils handling. Where significant quantities of fine‐grained materials are present, handling difficulties such as clay lumping, balling and sticking must be expected.

Figure 6-1: Assessment of Clogging Potential


6.0- TBM Tunnels


Such conditions will be found tunneling through the Lakewood, San Pedro and Fernando Formations. The excavated clay will be sticky, tend to clog the cutting wheel and be difficult to remove from the face. The clay is likely to produce a smear around the perimeter of the excavation.

Clay lumping, balling and sticking will occur within the working chamber and spoils handling system. It will require the use of conditioners and/or the use of water jets within the chamber to mitigate problems related to clay “stickiness”. However, the excavated clay is likely to be slick and difficult to handle in the presence of water. It will also be difficultrequire additional effort to separate in a slurry treatment plant, Therefore, the contractor must develop methods to efficiently excavate the clay, control the size of clay lumps, and transport the spoil using foam, bentonite, polymers or other conditioners that reduce the “stickiness” and “slickness” of the clay, and to have appropriate approaches for dealing with the fine grained material in the slurry separation plant.

The potential for soil clogging within the tunneling system has been assessed using a method proposed by Thewes and Burger (2004). An assessment of the clogging potential for the fine materials in the tunnel reaches in Section 1, are presented in Figure 6‐1Figure 6‐1. The atterberg limit tests were performed on fine‐grained soil types found within the tunnel envelope. For soils impacted by asphalt, the asphalt was burnt off before the tests were run and therefore, the results do not establish the clogging potential of the asphalt. For conditions within the tunnel reaches, the susceptibility to clogging for material without asphalt is estimated to be as follows:

Fine‐grained material of the San Pedro Formation having a medium to high risk of clogging.

Fine‐grained material of the Fernando Formation having a medium to high risk of clogging.

The impact of asphalt is discussed in Section 6.10.

6.6 Ground Support in Tunnels

6.6.1 Tunnel Lining

The one‐pass tunnel lining system, consists consisting of 12‐inch thick double gasketed precast concrete segments that are bolted and dowelled together to form a continuous circular lining, are specified as ground support for the tunnel. The double gaskets provide redundancy and a means for effecting leak repair to prevent leakage of groundwater and gas into the tunnel. The gasketed precast concrete tunnel lining installed by the TBM during excavation may serve as the final lining if project criteria for structural and seismic performance, leakage, and corrosion protection are satisfied. The minimum internal diameter for the tunnel is provided in the Project Definition Drawings.

The minimum internal diameter for each bored tunnel is provided in the Project Definition Drawings. The characteristics of the soils through which tunneling will occur are provided in Appendix B.

The soil parameters for design of the tunnel lining are provided in Appendix C for baseline purposes. These characteristics and parameters are to be based on the results of in‐situ and laboratory tests contained in the GDR, correlations to engineering properties, and engineering judgment and to be established by the Design‐Build Contractor. The permanent structural lining is required to be capable of resisting degradation when in contact with the anticipated natural soil, groundwater, and contaminants identified summarized in Appendix D.


May 22, 2013 Page 6-10


6.6.2 Backfill Grouting

To minimize ground loss, the void between the TBM excavation and the tunnel lining must be promptly immediately filled once as the lining is installed. The grout should be injected continuously through the tail of the shield as the shield is advanced. For adequate filling of the void, it is anticipated that a grout pressure will be required that is in excess of the surrounding soil and water pressures, and grout volumes must be placed behind the tail seals at a rate that is compatible consistent with excavation advance.

6.6.3 Break-Outs and Break-Ins with TBM

Excavation out of a station/shaft/tunnel into the ground (referred to as "break‐out") and excavation into a station/shaft/tunnel from the ground (referred to as "break‐in") requires ground treatment to stabilize the ground and minimize ground losses that would risk failure of tunnel or excavation, and prevent unacceptable movement of existing structures and utilities. At both break‐outs and break‐ins, groundwater control to prevent flooding and soil transport into the station/shaft/tunnel structures must be maintained. Any treated ground must stabilize the face yet be able to be excavated.

6.7 Spoil Handling and Disposal

6.7.1 Spoil Handling

EPB TBM ‐ Spoil handling must be set up to handle excavated material that has been conditioned in the working chamber of the TBM to maintain face stability. The spoils emerging from the working chamber of the EPB TBM will be a mixture of excavated material, conditioner, asphalt and water and will also contain gases, such as methane and hydrogen sulfide. The water can originate as groundwater or can be artificially added to condition the spoil. As a result of the conditioning, the spoil will contain additives and the water content will be different from that encountered in situ. When properly conditioned, the spoil can have the consistency of liquid waste and measures must be taken to suitably handle and dispose of the mixture. This will include stockpiling spoil on‐site to drain it, transport from site in sealed trucks and the use of an intermediate offsite stockpiling site to drain or dry the spoil to acceptable water content levels before disposal. Provisions must also be made for handling and disposal of the water draining from the spoil.

Slurry Shield TBM ‐ The spoil emerging from the working chamber of the slurry shield TBM will be slurry consisting of water, bentonite and excavated material. The slurry will transport the spoil to the surface where separation facilities will be located to separate the excavated material from the slurry. The slurry will be recycled to the face and the remainder, which is likely to contain slurry residue must be disposed. Where contaminated spoil (either natural or man‐made) is obtained from the tunnel, the Contractor must be capable of identifying and isolating the contaminated materials (slurry, water and excavated material) such that they can be disposed of in accordance with appropriate regulatory requirements.

Spoil Handling of Asphalt Impacted Soils ‐ Screens typically used in slurry separation plants were tested using asphalt impacted soils. The investigations indicated that water is readily removed from the tar sands and comes out clean with little residual left in the screened water. Little residual bentonite was left on the asphalt‐impacted soil and residual bentonite was easily removed by a clean water rinse.

Minute amounts of tar residue build up remained on the screens and eventually caused minor plugging of the screen media. This material was able to be removed with a steam cleaner. However, the material


6.0- TBM Tunnels


did not plug stainless steel screens at ambient, or temperatures under 200 degrees Fahrenheit. It is not anticipated that the asphalt impacted soils would clog equipment associated with the separation plant, such as screens, pumps, hydrocyclones or centrifuges.

The investigations (Clean Slurry Technology Inc., 2011) indicated that additives, such as polymers can assist with the handling of asphalt‐impacted soils. Oil is likely to be released from the asphalt by the surfactants that will make the material slippery and prevent the asphalt from sticking to metal surfaces. Using slurry shield TBM technologies, an additional step will be required in which the oil is separated from the muck by means of an oil skimmer. Special measures for handling, transportation and disposal will also be required.

6.7.2 Spoil Characterization

The design‐build contractor should develop its own estimate of the quantities of contaminated and non‐contaminated materials based on its layout of the excavations for the tunnels and cross passages, the information provided in Metro 2013i, and any additional information (such as additional borings) that it considered are needed to assess the contaminated ground conditions.

6.8 Gas Control The use of a closed face TBM is part of the controls considered necessary to successfully excavate the tunnels in the gassy ground. Other controls that the Contractor must consider and that can enhance safety when mining in “gassy” ground include but are not limited to:

Sufficient face pressure to reduce off gassing

Monitoring of gas levels, gas bubbles and gas pressure within the working chamber of TBM and modifying work activities accordingly

Reduction in rate of advance to reduce rate of gas inflows discharged from the screw conveyor

Control of spoil released from working chamber

Purging working chamber of gases

Addition of chemicals to neutralize gases

Enhanced tunnel ventilation

Enhanced monitoring of gas levels within the tunnel excavation

Further mitigation measures available include:

Injection of large quantities of hydrogen sulfide ‐free water into ground either through the tunnel face by means of probe holes or from the surface by means of through injection wells (spaced less than 15 ft on apart).

Treatment of the ground with dilute hydrogen peroxide either through the tunnel face by means of probe holes or from the surface by means of through injection wells (spaced less than 15 ft on apart).


May 22, 2013 Page 6-12


Addition of sodium hydroxide (NAOH) to maintain a pH of 10 and keep hydrogen sulfide in a dissolved state. Additives to increase pH were must be checked against oil‐field or other slurry excavation drilling experience, as some additives would can adversely affect slurry properties.

Use of a zinc “scavenger” to precipitate dissolved sulfide out of the slurry.

Soil‐gas extraction in unsaturated areas to remove the hydrogen sulfide from the ground. The technique is commonly used in the soil remediation work to reduce ground contamination.

Air injection in unsaturated areas to oxidize the hydrogen sulfide. The technique is commonly used in the soil remediation work to reduce ground contamination.

Note: Some remediation measures will be effective for only a limited period of time and it should be anticipated that pre‐treatment levels of gas will return.


7.0- Shaft and Stations Excavations


7.0 SHAFT AND STATIONS EXCAVATIONS

For the purpose of the baseline for shaft and station excavations:For the Section 1 shaft and station excavations, Ggeologic profiles for the stations and shaft are presented in Appendix A and the Eengineering characterization of soils and rock encountered is given in Appendix B.

Baseline values for engineering properties to be used for design of excavations are given in Appendix C.

Baseline chemical constituents within the ground and groundwater for which structural materials must be resistant to are presented in Appendix D.

The Design‐Build Contractor is responsible for developing the engineering parameters used for design.

7.1 Wilshire/Western Retrieval Shaft The Wilshire/Western Shaft excavation will be built about 20 feet west of the existing Wilshire/Western Station. The excavation will be approximately 135 feet wide by 40 feet long and excavated to a depth of about 65 feet below ground surface. The excavation will is anticipated to be supported by means of soldier piles and lagging with an internal system of walers and struts. Below 40 feet, the excavation can be supported with tiebacks, where feasible. The location of the excavation is shown on the Project Definition Drawings.

7.1.1 Subsurface Conditions at the Excavation at Wilshire/Western Shaft

The Wilshire/Western Shaft will be excavated through the following sequence of materials and soils:

Artificial Fill (af) – Below the pavement surface the fill consists of a depth of between four and sixteen feet of poorly graded sands with gravels.

Lakewood Formation and San Pedro Formation ‐ These deposits run the full length of the excavation. The Lakewood Formation consists primarily of dense silty sand and clayey sand (SM and SC) interbedded with medium stiff to stiff olive brown to yellowish brown sandy clay and sandy silt (CL and ML) and the underlying San Pedro (Lakewood Formation) and olive gray to greenish gray very stiff clays (San Pedro Formation) with layers and lenses of medium dense to very dense sands containing gravel (up to 2 inches) and occasional cobbles.

Siltstone of the Fernando Formation underlies the excavation at a depth of about sixteen feet below the bottom of the excavation.

Spoil Characterization ‐ Based on the environmental investigations, soil samples tested did contain constituents (tert‐butanol – see E‐101 in Metro, 2013i) that would classify them as environmentally impacted.

Tiebacks ‐ Tiebacks installed for temporary support of the Wilshire/Western Station are likely to be encountered at the eastern end of the shaft and will require removal during shaft excavation.


May 22, 2013 Page 7-2

Geotechnical Baseline Report 7.0 – Shaft and Stations Excavations

7.1.2 Groundwater

The historic high groundwater table is shown on the geologic profile at a depth of approximately 10 feet below ground surface. To account for the seasonal and annual variations in groundwater levels, the groundwater table should be taken as varying from 0 feet above to ten feet below the level shown on the geologic profile.

The sandy materials between 50 and 80 feet deep are anticipated to be the principal source of water with localized seepage also expected in the upper 50 feet of the excavation, particularly in the sandy zone. Groundwater inflows are estimated to be around 75 gallons per minutes. This is based on a hydraulic conductivity of 10‐3 centimeters per second for the sandy materials.

Groundwater Control ‐ It is anticipated that deep dewatering wells installed prior to excavation will be required to dewater the water‐bearing zone between 50 and 80 feet deep with gravel‐filled trenches and sump pumps controlling flows in the upper 50 feet. The site should be dewatered to maintain the groundwater at least five feet below the excavation bottom.

The dewatering system should be designed to ensure that environmentally impacted groundwater does not migrate off site onto adjacent properties.

Groundwater Disposal ‐ Based on the environmental investigations (metroMetro, 2013i), nearby wells (E‐102) indicated that the groundwater was environmentally impacted. It is anticipated that groundwater from dewatering operations at Wilshire/Western Shaft will require treatment prior to disposal.

NOTE: Only one boring was performed within the portion of the Western shaft site located on Wilshire Boulevard. The portion of the shaft located in a parking lot north of Wilshire Boulevard was not explored with any environment borings. At least one boring by the Design‐Build Contractor is needed in this area to evaluate potential environmental conditions.

7.1.3 Gases

Based on the current City of Los Angeles (2004 and 1996) “Methane and Methane Buffer” zone map, the shaft site is outside the city mapped methane zone. However, the geotechnical design summary report (Metro Rail Transit Consultants, September 1990) prepared for the Wilshire/Western station indicates that the station excavation was classified as “gassy” by the State of California, Department of Industrial Relations, Division of Occupational Safety and Health Administration (Cal/OSHA) at that time. During the station excavation, sulfur odor was detected in three borings and tar sands and traces of petroliferous earth materials were observed in two borings.

Based on the experiences from the Wilshire/Western Station construction, the shaft excavation will be classified as “gassy”.

7.2 Wilshire/La Brea Station Excavation The Wilshire/La Brea Station excavation will be located on Wilshire Boulevard between Detroit Street and to just east of Orange Drive. A station and a double cross over will be constructed within the excavation. The location of the excavation is shown on the Project Definition Drawings.




The site is bounded to the north by buildings including a high rise office building, single story retail, five story commercial building and at the eastern edge of the excavation a six story apartment building and the south by commercial buildings ranging from high rises to single story retail buildings.

The station box will be approximately 980 feet long and vary between approximately 58 feet and 67 feet wide. It will be excavated to a depth of between 70 and 80 feet. The excavation is to be supported by means of soldier piles and lagging with an internal system of walers and struts. Below 40 feet, the excavation can be supported with tiebacks.

7.2.1 Subsurface Conditions at the Excavation at Wilshire/La Brea Station

The excavation at the Wilshire/La Brea Station will encounter the following sequence of materials and soils:

Artificial Fill (af) – Below the surface pavement comprising up of 6 to 8 inches of asphalt concrete overlaying 8 to 12” of Portland cement concrete, the fill varies from zero feet up to approximately sixteen feet across the site. The fill is silty sand.

Fine Grained Deposits – Younger Alluvium, Lakewood Formation and the top of the San Pedro Formation ‐ These deposits run the full length of the excavation ranging from approximately 30 to 55 feet thick. They consist primarily of medium stiff to stiff clays and silts (ML, CL, CL‐ML, CH) but have two layers, approximately 5 to 10 feet thick, of medium dense to dense silty sands, clayey sands and sands (SM, SP‐SM,SC).

Coarse Grained Deposits of the San Pedro Formation ‐ This deposit underlies the full extent of the fine grained deposit in the station excavation. Its thickness to the bottom of the station box varies from approximately 20‐30 feet. It is made up of dense to very dense poorly graded sand and silty sand (SM, SP, SP‐SM, GW and GM).

Fernando Formation underlies the excavation at a depth of between five feet and ten feet below the bottom of the excavation.

Spoil Disposal ‐ Volatile organic compounds (VOCs) were detected in samples from borings that would classify them as environmentally impacted.

Although metals were detected in the soil samples, they are likely representative of typical background concentrations for soils in the vicinity of the boring locations.

Abandoned Oil Wells – Two oil wells are identified at the eastern end of Wilshire/La Brea Station. No definitive evidence was obtained regarding the exact location of these wells but the areas within which they are located are shown in Appendix A. Refer to Section 5.3, Abandoned Oil Wells and facilities for further details regarding oil well obstructions and their abandonment.

7.2.2 Groundwater

The historic groundwater table is shown on the geologic profile at a depth of approximately 10 feet below ground surface. To account for the seasonal and annual variations in groundwater levels, the groundwater table should be taken as varying ± five feet from the level shown on the geologic profilefrom 0 feet above to ten feet below the level shown on the geologic profile in Appendix A.


May 22, 2013 Page 7-4


The sandy materials between 55 and 85 feet deep are anticipated to be the principal source of water with localized seepage also to be expected in the upper 55 feet of the excavation, particularly in the sandy zones. Groundwater inflows are estimated to be around 350 gallons per minutes for a 980 foot long excavation using a hydraulic conductivity of 10‐3 centimeters per second for the sandy materials.

Groundwater Control ‐ It is anticipated that deep dewatering wells installed prior to excavation will be required to dewater the water‐bearing zone between 55 and 85 feet deep with gravel‐filled trenches and sump pumps controlling flows in the upper 55 feet. The site should be dewatered to maintain the groundwater at least five feet below the excavation bottom.


Groundwater Characterization for Disposal – The analytical test results of groundwater samples showed the presence of chlorinated solvents (1, 1‐Dichloroethene, cis‐1, 2‐Dichloroethene (cis‐1, 2‐DCE), Trichloroethylene [TCE]) and, fuel‐related constituents including Toluene, MTBE, and total petroleum hydrocarbons such as diesel/oil (TPH‐d/o). The suspect sources are a SLIC (Spills, Leaks, Investigation and Cleanup)‐listed facility, former service stations, and a dry cleaning facility located between 5347 and 5351 Wilshire Boulevard (near the intersection of Wilshire Boulevard and Detroit Street). The results indicate the station excavation is considered environmentally impacted and groundwater needs treatment prior to disposal.

7.2.3 Gases

The excavation for the Wilshire/La Brea Station will be classified as “gassy” by Cal/OSHA.

Conditions within the excavation will vary with location and with depth. It is anticipated that the following represent the maximum gas conditions to be encountered within the groundwater and within the pore spaces in the vadose zone for the excavation:

Methane levels at two percent, and/ or

Hydrogen Sulfide levels at two ppm


Information from the Exploratory Shaft construction on off gassing from the ground will be provided once it becomes available.

7.3 Wilshire/Fairfax Station Excavation The Wilshire/Fairfax Station will be built within a station box located in Wilshire Boulevard. It extends from about 580 feet east of Fairfax Avenue to about 260 feet west of Fairfax Avenue. Excavations for appendages are required on the north side of the box east of Orange Grove Avenue and on the south side of the box near Orange Grove Avenue.

The site is bounded to the north by buildings associated with the Los Angeles County Museum of Art and Hancock Park, where the Page Museum and the La Brea Tar Pits are located and to the south by commercial and residential buildings.




The station box will be between approximately 58 feet and 67 feet wide and approximately 850 feet long. It will be excavated to a depth of between about 65 to 70 feet. The excavation is to be supported by means of soldier piles and shotcrete lagging with an internal system of walers and struts. The location of the excavation is shown on the Project Definition Drawings.

7.3.1 Subsurface Conditions at the Excavation at Wilshire/Fairfax Station

The excavation at the Wilshire/Fairfax Station will be excavated through the following sequence of materials and soils that are also a source of fossil remains:

Artificial Fill (af)–– Below the surface pavement comprising an 11‐inch thick asphalt concrete layer, the fill varies across the site from one foot up to approximately nine feet thick. The fill material primarily consists of heterogeneous mixture of clays, silts and sands. Rubble present in the fill is expected to have a maximum size of 3 ft.

Between Fairfax Avenue and Orange Grove Avenue, an ancient channel approximately 170 feet wide and about 9 foot deep is incised into the older alluvial deposits. The channel is filled with Younger Alluvium up to five feet thick and artificial fill. The Younger Alluvium consists of layers of loose silty sand (SM) with layers of silts (ML).

Older Alluvium and Lakewood Formation. Beneath the fill to a depth of approximately 40 feet at the west end of the box and reducing to about 25 feet at the east end of the box, the soils are the Old Alluvium and the Lakewood Formations. They are primarily stiff to very stiff fine –grained soils (ML, CL, CL‐ML and CH) with inter‐layered medium dense to dense coarse‐grained lenses (SM, SC, SP‐SM) with occasional gravel and cobbles. The Older Alluvium and Lakewood Formation are impregnated with asphalt from a depth of about 10 9 feet to 25 feet below ground surface. Small pods of tar (encountered in the borings) are to be expected as well as hydrogen sulfide and methane released from the ground, groundwater and asphalt.

San Pedro Formation ‐ Below the Older Alluvium and Lakewood Formation to the bottom of the excavation at a depth of about 70 feet ( a thickness of approximately 30 feet at the west end of the station and approximately 50 feet at its east end), the soils consist of the San Pedro Formation. These soils are coarse‐grained and comprise dense to very dense sand layers (SC‐SM, SC, SM, SP, SW, SP‐SM, SW‐SM, and GM) with occasional gravel and cobbles and occasional clay layers (CH, CL‐ML). They are asphalt impacted to the full depth of the excavation. The asphalt content increases with depth from approximately 4 percent to 16 percent.

Fernando Formation to the east is about ten feet below the station bottom and slopes down to the west to about 50 feet at least 20 feet below the excavation bottom.

Spoils Characterization ‐ The majority of the station excavation will be performed within the asphalt‐impacted soils. These soils contain from 0 percent to 25 percent, with an average of 15% asphalt (by weight) and start at depths of about 10 to 25 feet below ground surface.

Analytical testing of soil samples collected from borings advanced in, or within 100 feet of, the station footprint indicates that the soils are environmentally impacted. The results of the “fish kill” tests indicated that they can be sent to a Class II Landfill; however, naturally occurring asphalt‐impacted soils may not be acceptable as daily cover material in certain Class II landfills (refer to Metro 2013i for further discussions on spoil disposal restrictions). Note: the accepted disposal criteria for soils impacted with hydrocarbons are specific to each disposal facility.


May 22, 2013 Page 7-6


Abandoned Oil Wells ‐ The station site is located within the historic Salt Lake Oil Field. Oil well “Salt Lake” 10 is located roughly in the northwest quadrant of the intersection of Fairfax Avenue and Wilshire Boulevard with an approximate location west of the Johnie’s Restaurant building. According to DOGGR records, “Salt Lake” 10 is an “idle oil well” which is an industry term to define a well that is out of production and inactive but has not been abandoned.

No definitive evidence was obtained regarding the exact location of “Salt Lake” 10 but the area within which it is located is shown in Appendix A. Refer to Section 5.3, Abandoned Oil Wells and facilities for further details regarding oil well obstructions and their abandonment.

7.3.2 Paleontological Monitoring Zone

The excavation includes a Paleontological Monitoring Zone (referred to as “Paleo Zone”). This is a zone potentially rich in fossil remains, similar to those found at the La Brea Tar Pits. Because of their scientific significance, this zone is to be excavated carefully and investigated to identify and, if found, recover fossils. Although associated with the asphalt impacted soils, the “Paleo Zone” does extend into soil not impacted with asphalt. For baseline purposes, the “Paleo Zone” is from the ground surface at approximate El. 165 to the top of the marine sediments at El. 145 at the Wilshire/Fairfax station excavation site and including any excavations for appendages associated with the station. However, due to disturbance at the ground surface, restrictions on excavation will not start until 10 feet below ground surface.

Within this zone, excavation techniques are specified and the paleontological monitor will observe the construction to determine whether fossils are present. Should fossils be identified, Metro will direct the Contractor how to proceed. Metro will also determine whether the extent of the zone to be searched should be modified and will direct the Contractor accordingly based on the procedures described in the General Requirements Section 01 35 92, Paleontological Coordination. The fossilized material to be removed using special excavation techniques has not been quantified and the contract has payment provisions to address the removal of fossils from the excavation.

7.3.3 Groundwater

The historic high groundwater table is shown on the geologic profile. To account for seasonal and annual variations in groundwater levels, the groundwater table should be taken as varying from 0 feet above to 10 feet below the level shown on the geologic profile. Overall, at the station site, the groundwater measurements indicate perched or semi perched groundwater conditions both above and within the asphalt impacted soils in coarse grained soils with the low permeability asphalt‐impregnated soils acting as water barriers.

The asphalt influences the soil hydraulic conductivity and also the performance of monitoring wells where screens have been placed in asphalt impacted soils. In some monitoring wells, groundwater could typically not be measured due to the asphalt seeps blocking the screens.

Groundwater inflows from the asphalt impacted soils into the excavation are estimated to be a maximum of 50 gallons per minute. Based on the information concerning the LACMA Underground parking structure, there is the potential for an additional and concentrated inflow of up to 200 gallons of water and hydrocarbon product locally entering the excavation through a fracture or vent in the




Lakewood or San Pedro Formations in a short period of time (10 minutes). The Contractor must develop procedures to deal with one such event.

Groundwater Control – The asphalt‐impacted soils are not expected to yield much water, although water seepages can be anticipated from semi‐perched water zones. This is substantiated by the experience available from excavations for building basements in this area. In most cases, excavations to depths of about 60 feet below ground surface have been dug without extensive dewatering systems. Therefore, deep wells for groundwater control are not anticipated for the station excavation. Nevertheless, as the excavation proceeds with conventional soldier pile and lagging system, water inflows should be expected and it is anticipated that such inflows can be controlled using gravel‐filled trenches and sump pumps.

Groundwater Characterization for Disposal – Based on the environmental investigations (Metro, 2013i), the groundwater from the station excavation is considered environmentally impacted with VOCs and TPH and needs treatment prior to disposal.

The water is contaminated with asphalt and derived products and will be a source of methane and hydrogen sulfide gases. Analytical laboratory results showed the presence of TPHs and VOCs. The presence of such constituents will require pretreatment of the groundwater prior to discharge into the municipal storm drain system under a National Pollution Discharge Elimination System (NPDES) permit. Other constituents found in the groundwater that affect its disposal are reported in Metro, 2013i.

7.3.4 Asphalt

Asphalt being a fluidviscous, is anticipated to migrate through the soil formations into the excavation through exposed walls and excavation bottom. With the soldier pile and lagging system in place, the asphalt will seep through weep holes and between lagging. It will clog the weep holes unless they are regularly maintained. Total asphalt inflows into the completed excavation are estimated to be a maximum of 40 gallons per day.

Since the asphalt will be under pressure at depth, upon excavation of the soils, it will off gas and be a source of methane and hydrogen sulfide in the excavation.

7.3.5 Gases

The excavation for the Wilshire/Fairfax Station will be classified as “gassy” by Cal/OSHA.


Methane levels at 100 percent, and/ or


Gases beneath the groundwater table will be under pressure equivalent toup to 5psi above the hydrostatic head.


May 22, 2013 Page 7-8


7.4 Wilshire/La Cienega Station The Wilshire/La Cienega Station will be built within a station box located in Wilshire Boulevard between La Cienega Boulevard and Tower Drive. Appendage excavations are located on La Cienega Boulevard, north of the excavation. The excavation consists of both the station and a double cross over.

The site is bounded by commercial buildings ranging from a ten story high rise office building to single story retail buildings

The station box will be approximately 1,000 feet long and vary between about 58 and 67 feet wide. It will be excavated to a depth of about 70 feet. The excavation will be supported by means of soldier piles and lagging with an internal system of walers and struts. Below 40 feet, the excavation can be supported with tiebacks. The location of the excavation is shown on the Project Definition Drawings.

7.4.1 Subsurface Conditions at the Excavation at Wilshire/La Cienega Station

The excavation at the Wilshire/La Cienega Station box will encounter the following sequence of materials and soils:

Artificial Fill (af) – Below the surface pavement comprising a 10 inch thick concrete slab, the fill varies from approximately 1 to 12 feet across the site. It consists of overlying clay, sandy clay and clayey sand backfill. The fill extends for a distance of about 460 feet long over the eastern central portion of the station excavation.

Younger Alluvium, Older Alluvium and San Pedro Formation – Primarily these deposits are fine‐grained and encountered below the fill to well below the depth varying of excavation. They consist primarily of clays and silts (CH, CL, CL‐ML, MH and ML) but do include lenses and layers of coarse‐grained material that have significant horizontal continuity across the excavation. The coarse‐grained layers include:

– Layer of sand and silty sand (SM, SW‐SM and SC) up to ten feet thick extending about 500 feet eastward from the west boundary of the excavation.

– Layer of predominately silty sand and clayey sand (SW, SC, SM, and SW‐SM, SP‐SM, SP, SP‐SC) (Older Alluvium and San Pedro Formation) found at depths between about 50 to 75 feet below ground surface that is continuous, up to 20 feet thick and covers the greater part of the excavation bottom.

Spoils characterization ‐ Based on the environmental investigations, soil samples did contain constituents that would classify them as environmentally impacted.

7.4.2 Groundwater

The historic high groundwater table is shown on the geologic profile at a depth of approximately 10 feet below ground surface. To account for the seasonal and annual variations in groundwater levels, the groundwater table should be taken as varying ± five feet from the level shown on the geologic profilefrom 0 feet above to 10 feet below the level shown on the geologic profile in Appendix A.

Groundwater level measurements indicate artesian pressure conditions in water bearing zonesthat water‐bearing zones confined by less permeable zones are under artesian pressure although the




water head does not exceed the overlying groundwater table. This is consistent with an artesian area delineated by Mendenhall (1905), which encompasses the station site.

The sand layer at a depth of about 50 to 75 feet is anticipated to be the principal source of water with localized seepage also expected in the upper 50 feet of the excavation. Groundwater inflows are estimated to be up to 140 gallons per minutes for a 1,000 foot long excavation based on the results of pump tests.

Groundwater Control ‐ It is anticipated that deep dewatering wells installed prior to excavation will be required to dewater the water‐bearing zone between 50 and 75 feet deep with gravel‐filled trenches and sump pumps being used to control flows in the upper 50 feet by collecting and pumping out of excavation. The site should be dewatered to maintain the groundwater at least five feet below the excavation bottom.


Groundwater characterization for Disposal – Based on analytical test results, the groundwater samples detected the presence of VOCs (cis‐1, 2‐DCE, Di‐chlorodifluoromethane) and low levels of Total Petroleum Hydrocarbons as diesel/oil (TPH‐d/o). The groundwater from the station excavation is considered environmentally impacted and needs treatment prior to disposal.

A more comprehensive groundwater analytical testing program performed during pump testing of the aquifer (located at depths of 50 and 75 feet from P‐101) indicated that copper and selenium concentrations are above daily maximum effluent limitations. NPDES testing done on four wells also indicated that various metals (chromium III, copper, lead, nickel and zinc) concentrations were above daily maximum effluent limitations, confirming that gGroundwater cannot be discharged into storm drains under a National Pollution Discharge Elimination System (NPDES) permit. As a result of metal concentrations (chromium III, copper, lead, zinc, nickel and selenium being above daily maximum effluent limitations, a A treatment system may be designedwill be required to treat metals prior to discharge into the storm drain under an NPDES permit. Alternatively, groundwater can be disposed into a sanitary sewer after obtaining an Industrial Wastewater permit. Pretreatment is likely to be required to allow off‐gassing prior to disposal into sanitary sewer.

7.4.3 Gases

The excavation for the Wilshire/La Cienega Station will be classified as “gassy” by Cal/OSHA.


Methane levels at 100 percent, and/ or




May 22, 2013 Page 7-10


7.5 Initial Ground Support at Station and Shaft Excavations Lateral earth pressure diagrams for the initial ground support system for the excavations are given in on the Project Definition DrawingsGeotechnical Design Memoranda (Metro, 2013k and m). Similar subsurface conditions on other Metro Rail projects have required soldier piles with timber or shotcrete lagging, tangent pile walls, and slurry walls as initial excavation support. Because of the depth of the cut‐and‐cover station excavations, struts or tiebacks or a combination of both will be required for lateral support. For satisfactory performance, the soldier pilesinitial support must be adequately embedded to resist the anticipated lateral loads.

Soldier piles and lagging systems will require dewatering operations prior to excavation and/or groundwater control during excavation.

Once an excavation is supported by soldier piles and lagging, the migration of sand and possibly siltsoils through the lagging must be prevented by measures such as placement of filter materials behind the lagging in areas where raveling or water seepage (due to residual inflows, perched groundwater inflow or broken utilities) persists. Provisions must be implemented to prevent the piping of fines from the alluvial soils and, if awhere relatively impermeable lagging (i.e. shotcrete) is used, effective drainage must be provided to reduce pressure on the support system.

7.6 Anticipated Ground Behavior at Excavations The excavated materials include both fine‐ and coarse‐grained deposits with particle sizes ranging from less than No. 200 sieve to granular material containing sands, gravels and occasional cobbles. Exposed soil conditions within the shaft and station excavations will vary. Changes will be gradational or abrupt, and will occur across the exposed surface as the excavation is deepened. During excavation, the height of exposed ground prior to lagging placement must be controlled to eliminate raveling and ground loss. The height of exposed ground prior to placement of lagging should be limited and meet the Technical Requirements Section 31 23 43, Shaft and Station Excavation.

In general, the deposits should stand long enough to permit placement of lagging prior to sloughing of side walls. However, the Contractor in all excavations must expect to locally encounter uUnsaturated sand, silt, silty sand, and clayey sand which are moist or have some apparent cohesion and will ravel (within an hour) from unsupported sidewalls. In gGravel, gravelly sand, poorly‐graded sand and silty sand above the groundwater table, unsupported sidewalls will ravel rapidly (within a few minutes) and running1 conditions should be anticipated. Flowing2 conditions must be anticipated in gravelly sand, poorly‐graded sand, and well‐graded sand below the water table or in the presence of semi‐perched groundwater. Large areas of unsupported soft fine‐grained soils will ravel3or squeeze into the

1 Running ground is defined as cohesionless material above the water table that runs immediately from unsupported sections of the tunnel and accumulates below the location of the run. 2 Flowing ground is defined as ground combined with water that immediately flows (like a viscous fluid) out of unsupported sections of tunnel. 3 Raveling ground is defined as ground that gradually sloughs or breaks up and falls out of unsupported sections of roof and sidewalls, leaving a cavity that increases in size with time.




excavations, particularly where seepages from perched ground water occur. The development of raveling, running and flowing conditions will be aggravated by the presence of gas within the ground and groundwater. When excavating the soils, the release of the in situ earth pressure as a result of excavation, the subsequent release of gas from the groundwater and asphalt, and the flow of gas, water and viscous asphalt through both coarse and fine‐grained soils will contribute to the breakdown of exposed walls.

For the Asphalt asphalt impacted soils are found at the Wilshire/Fairfax Station excavation, .stand‐up time will be similar to that described above for both coarse‐ and fine‐grained soils. The asphalt does not act as a binding agent to the soils. It will flow out of exposed surfaces with groundwater bringing soil material with it and both groundwater and asphalt will flow and squeeze through holes or gaps in the lagging support system once this is in place.

The excavations will produce gas. The gas will be found in voids in the soils and from off gassing of the groundwater and the asphalt. Soils comprising, silt, silty sand, and clayey sand impacted with asphalt will exhibit apparent cohesion and can be expected to stand for up to 24 hours before starting to ravel from unsupported walls if groundwater is properly controlled. However, the height of exposed ground prior to placement of lagging should be limited and meet the Technical Requirements Section 31 23 43, Shaft and Station Excavation.

7.7 Excavation Methods Excavations for stations and cut‐and‐cover sections of tunnel can be achieved using conventional excavation methods. Suitable drilling equipment can be used to drill holes for installation of the soldier piles for the initial support system with suitable heavy‐excavation equipment required to excavate for the stations and cut‐and‐cover sections, the very dense alluvium containing gravel and cobbles, ground that has been grouted, artificial fill containing concrete, asphalt rubble, and wood fragments. Excavation methods through the fill must be able to remove rubble up to 3 feet in dimension and to detect abandoned and functioning utilities. The Contractor will be required to locate abandoned and functioning utilities prior to the installation of initial support system and excavation, and relocate where necessary.

7.7.1 Drilling for Soldier Piles

To mitigate disturbance to the public, driving of soldier piles is not permitted. Therefore, drilled piles or piles installed using sonic or vibratory drivers must be used. Drilling rigs must have sufficient capacity/torque to penetrate dense to very‐dense Lakewood and San Pedro Formations containing gravel and cobbles and the Fernando Formation (siltstone with hard concretions and hard layers). The Contractor must take into account drilling conditions that include caving of holes and deviation of holes.

Instability of drilled holes for piles and tiebacks is to be anticipated when granular alluvial soils containing sand, gravel, and/or cobbles are encountered both above and below the water table. Casing or slurry will be required to prevent instability. Where caving occurs, it will result in large backfill and/or tieback anchorage quantities. Casing water, water and polymers, or slurry can be used to prevent and minimize caving. The Contractor must take into account drilling conditions, including deviation of borings as a result of encountering cobbles, and should also utilize appropriate drilling techniques,


May 22, 2013 Page 7-12


control the drilling rate and limit the number of passes down the hole to mitigate hole caving, and have casing available at the job site for rapid use.

Deviation of holes will be caused by deflection of the drilling tool when it encounters obstruction in fill (up to 3 feet in size), cobbles in the Alluvium, Lakewood and San Pedro Formations, and hard concretions and layers within the Fernando Formation. A coring bit should be available to drill through materials that will deflect the drill tool. Core drilling, backfilling of holes and redrilling are likely to be necessary to correct hole deviations.

Should casing be used in supporting drilled holes in asphalt impacted soils, consideration must be given to casing removal. It should be expected that asphalt squeezing out of the soil and coating the wall of the drill hole is likely to make casing removal difficult. Drilling eequipment would need to be sufficiently powered to extract the casing. It is recommended that prior to using casing in asphalt‐impacted soil, the Contractor carry out a field demonstration to confirm that techniques are available to readily extract casing from the ground.

While drilling through the Paleo Zone, the paleontological monitor will be on site, observing the drilling operations to determine whether fossils are present. Fossils found in the drill cuttings will be collected.

Additives and slurries introduced into the soldier pile drilling TBM operations to prevent caving must be effective over the full range of ground and groundwater chemistries encountered and characterized in Appendix D.

The discussion related to drilling for Soldier Piles also applies to other hole drilling for the work including drilling for tieback installations. It should be noted that caving in tieback holes would result in large anchorage volumes.

7.7.2 Shaft Excavation

For all ground conditions during excavation for shaft and stations, the height of ground exposed in an excavation should be restricted as indicated in Technical Requirements Section 31 23 43, Shaft and Station Excavation to ensure that the ground does not ravel. Once the excavation is supported, water build‐up behind the lagging must be prevented by measures such as placement of filter materials behind the lagging in areas where water seepage (due to residual inflows, groundwater inflow or broken utilities) persists.

Shaft Excavation in the Artificial Fill‐ The fill will contain concrete (up to 3 feet in size), asphalt rubble, and wood fragments as well as compacted soil backfill. The contractor will be required to locate abandoned and functioning utilities in the fill prior to the start of excavation and relocate where required, dense alluvium containing gravel and cobbles, ground that has been grouted.

It is anticipated that excavations in the fill can be achieved using suitable equipment such as a track mounted hydraulically operated backhoe. The equipment must be able to remove rubble up to 3 feet in dimension. During excavation, the height of ground exposed in the excavation should be restricted to ensure that the ground does not ravel and water build‐up behind the lagging must be prevented.




Shaft Excavation in Soils Not Impacted by Asphalt – The excavations at Wilshire/Western shaft, Wilshire/La Brea Station and Wilshire/La Cienega Station are in soils that are not impacted by asphalt and not designated as a Paleontological Monitoring Zone. ‐ It is anticipated that excavation for these stations can be achieved using conventional excavation equipment such as track mounted hydraulically operated backholes.

Shaft Excavation in Asphalt – Impacted Soils ‐

Difficulties should be anticipated operating excavation equipment in asphalt impacted soils. At the Wilshire/Fairfax station, stiff to hard petroliferous silts and clays and dense to very dense tar sands will be encountered within the excavation.

The asphalt‐impacted silts, clays and sands will deteriorate rapidly in the presence of water to form a thick, sticky, oily sandy/silty/clayey slurry that will be messy and abrasive to equipment. Groundwater control within the excavation is necessary to minimize the deteriorating wall and bottom conditions. however, Temperature will also influence the conditions in the excavation.

Under the daily temperatures typically encountered in Los Angeles, the exposed asphalt impacted soils on which construction equipment must operate is expected to behave as a soft soil. Operation of construction equipment in the tar sands will be messy, requiring remedial measures such as use of geogrid or gravel. In previous excavations, the contractor has laid down lumber or a gravel layer to facilitate the movement of the heavy equipment on asphalt impacted soils. At the design subgrade level it will be necessary to stabilize the bottom by placing a layer of course coarse gravel prior to pouring a base slab.

Shaft Excavation in “Paleo Zone” – See Section 7.3.2. Since the Paleo Zone is primarily within the asphalt‐impacted soils, the difficult conditions are described above.

For all ground conditions during excavation for shaft and stations, the height of ground exposed in an excavation should be restricted as indicated in Technical Requirements Section 31 23 43, Shaft and Station Excavation to ensure that the ground does not ravel. Once the excavation is supported, water build‐up behind the lagging must be prevented by measures such as placement of filter materials behind the lagging in areas where water seepage (due to residual inflows, perched groundwater inflow or broken utilities) persists.

7.8 Gas Controls For the station and shaft excavations, the Design‐Build Contractor must consider equipment and excavation methods that can enhance safety when excavating through “gassy” ground. Such measures can include but are not limited to:


Enhanced ventilation

Enhanced monitoring of gas levels within the excavation


May 22, 2013 Page 7-14


7.9 Permanent Station Structures The permanent station structures will consist of a reinforced concrete structure constructed within excavations. The structures will have a gas and water proofing barrier system to prevent leakage into the stations. The structures will be designed by the Design‐Builder Contractor for the soil and groundwater conditions at each station location. These conditions are characterized in Appendices A, and B and D while the geotechnical design parameters to be used at each station site are provided in Appendix C.

Preliminary evaluations of the geotechnical data to determine engineering parameters for design of temporary or permanent work are presented in the Geotechnical Design Memoranda for the stations and shaft (Metro, 2013 k and m). The Design‐Built Contractor must review the data in the GDRs and Geotechnical Design Memoranda and determine that its own parameters to design the elements of the work and that will be consistent with the proposed means and methods of construction.

Geotechnical design considerations not specifically addressed by the Metro Design Criteria that should be addressed by the Design‐Builder Contractor include but are not limited to:

Prevention of gas and water leakage into structures at joints between station boxes and station entrances, and between station boxes and tunnels. The joints should be designed to accommodate differential movements and distortions resulting from settlements, changes in groundwater levels (from discontinuing construction dewatering and long term changes), and from seismic events.

Potential liquefaction at sites. For example, Wilshire/La Cienega Station is located within a potentially liquefiable zone as identified on the liquefaction hazard map prepared by the California Geological Survey. The Design‐Build Contractor should evaluate the potential liquefaction at the site for the station box and the station entrance and factor this into its design and construction.

T o account for sSeismic demand due to racking deformations at the Wilshire/Fairfax Station, . This requires adopting a numerical modeling approach that accounts for the structural properties, varying soil stratigraphy and soil properties, loadings and deformations. This will provide be a more rigorous analysis that can optimize design rather than using the semi‐closed form solution.

Ensuring that the water and gas barrier systems preventing leakage is are effective under the artesian water pressures that will be encountered at the Wilshire/La Cienega Station.


8.0- Mined Excavations


8.0 MINED EXCAVATIONS

Mined excavations (defined as underground openings that are not excavated using a TBM) will be required to construct the cross passages and cross passages with sumps.

The Design‐Built Contractor is responsible for developing the engineering parameters used for the design of the mined excavations.

8.1 Cross Passages and Cross Passages with Sump Structures Cross passages connecting the parallel tunnels are required at a minimum of 23 locations along the subway alignment with three also serving as sump structures. The cross passages and cross passages with sump structures are indicated on the project definition drawings.

The requirements for the final configuration of the cross passages are provided in the Metro Design Criteria. To meet these criteria, the size of the excavation with initial ground support installed for each cross passage will be a minimum of 14 feet‐6 inches wide by 17 feet‐0 inches high. Where sumps are required the depth to the bottom of sump excavation will be about 7 feet – 6 inches.

8.1.1 Subsurface Conditions

The cross passages are shown on the geologic profile in Appendix A.

Since the geologic units are heterogeneous, subsurface conditions at each mined excavation will vary within the exposed face and will change within a short distance as the excavation is advanced. Where few fines are present and the soil is granular, raveling, runs, or flows will occur that if not controlled will result in ground movements. To avoid settlements that adversely affect overlying utilities and structures, ground treatment is required at mined excavation locations.

8.1.2 Groundwater

The groundwater level is shown on the geologic profile (Appendix A). For baseline purposes, the groundwater level at each cross passage location is expected to remain within a range from 0 feet above to 10 feet below the groundwater level shown on the geologic profile.

8.1.3 Gases

All cross passage excavations will be classified as “gassy” by Cal/OSHA. Prior to excavation of each cross passage, the ground should be probed to evaluate the potential for off‐gassing from fissures or from groundwater inflows.

Section 1 tunnel route passes through the City of Los Angeles designated “Methane Zone”. Additionally, the reach Along Wilshire Boulevard between Highland Avenue and Stanley Drive has elevated levels of methane and hydrogen sulfide identified by the site investigation program. The baseline gas conditions are indicated on the geologic profiles shown in Appendix A.

8.1.4 Ground Improvement

For cross passage excavations in soil (San Pedro Formation), ground treatment, e.g., with chemical or cement grout, is required prior to break‐out to: improve the ground strength and stabilize the ground


May 22, 2013 Page 8-2

Geotechnical Baseline Report 8.0 – Mined Excavations

around the existing tunnels; to increase stand up time for the excavation to allow installation of ground support; and, to control or limit groundwater and gas inflows during excavation. As part of the design for the ground improvement program, the Design‐Contractor is required to investigate the subsurface conditions with a minimum of one exploratory boring at each cross passage location. For cross passage excavations in the siltstone (Fernando Formation), the Design‐Build Contractor should investigate by means of horizontal probe holes whether subvertical fractures containing groundwater or asphalt or gases are present.

The ground improvement program should limit groundwater inflows to each cross passage excavation during construction to meet the inflow criteria indicated in Technical Requirements Section 31 71 16, Mined Cross Passages. Within the excavation, the flow should be channeled by a system of weep holes, drains and sumps.

Should conditions in the field indicate that the ground treatment has not been fully effective, i.e., untreated soils are exposed or exposed ground is raveling or groundwater greater than specified amounts are entering the heading then additional measures must be taken to stabilize the ground that may include reducing the spacing of support, installing forepoling to provide immediate support of the ground or undertaking additional grouting.

Should the limitation of groundwater inflows by ground treatment prove ineffective in controlling gas inflows to the excavation during construction, then additional ventilation of the heading will be required to reduce methane and hydrogen sulfide levels to levels acceptable to Cal/OSHA regulations.

8.1.5 Method of Excavation

Methods of excavation and initial support for the cross passages and the sump structure must prevent soil losses and ground water inflows that could deprive the tunnel support system of the passive ground reaction necessary for stability, must protect against instability at the face of the cross passage excavation, must limit surface settlements, and minimize damage to structures and buried utilities.

To stabilize the mined excavations and to limit surface settlement and damage to existing structures, , the excavation sequence and round length must be adequately controlled by the Contractor. A heading and bench excavation is anticipated for the cross passage excavation. Where fine grained soils below groundwater level are encountered at the invert, crushed rocks or mud slab will be required to stabilize the invert.

8.1.6 Initial Ground Support

The design of the initial support for the cross passages between tunnels and for sump structures includes the temporary support of the break‐outs and break‐ins to the tunnels and is the responsibility of the Design‐Build Contractor.

Prior to removing tunnel lining segments at cross passage locations for break‐outs, the existing linings for the tunnels must be supported and protected over a sufficient length to maintain their stability and non‐distorted shape. The support must also ensure that the excavation perimeter remains fully supported. It is anticipated that the initial ground support for the cross passages will consist of lattice girders and shotcrete or steel ribs with lagging or steel liner plate. With the application of ground


8.0- Mined Excavations


treatment, it is anticipated that initial support will be installed on a spacing not exceeding four feet provided that the support is installed immediately the ground is exposed.

8.1.7 Anticipated Ground Behavior during Construction

Methods of excavation and initial support for the cross passages and the sump structure must prevent soil losses that could deprive the tunnel support system of the passive ground reaction necessary for stability and must limit surface settlements, minimize damage to structures and buried utilities and control or limit groundwater inflow during excavation.

The requirements for protection of buildings along the alignment are defined in the Technical Requirements Section 31 71 19, Excavation by Tunnel Boring Machine and for protecting utilities in Technical Requirements Section 33 01 00, Maintenance and Support of Utilities. The purpose of the protection measures is to eliminate damage to the types of structures encountered along the alignment or limit it to cosmetic damage only.

8.1.8 Gas Controls

For the cross passages excavated using sequential excavation methods of mining, the Design‐Build Contractor must consider the type of equipment to be used and excavation methods that can enhance safety when excavating through “gassy” ground. Such measures include but are not limited to:

Groundwater treatment to remove gases


Enhanced ventilation

Enhanced monitoring of gas levels within the excavation

8.1.9 Permanent Structural Lining

The final linings for the cross passages and cross passage with sump structures will consist of reinforced concrete structures constructed within the mined excavations. The structures will have a gas and water proofing barrier system between the initial support and the final lining to prevent leakage into the cross passages (see Technical Requirement Sections 07 10 00, Water and Gas Protection Systems and 07 13 65, Hydrocarbon‐Resistant Membrane). The linings for the cross passages and where required, sump structures will be designed by the Design‐Builder Contractor for the particular soil and groundwater conditions at each cross passage location. These conditions are characterized in Appendices A, and B and D while the geotechnical design parameters to be used at each station site are provided in Appendix C..

See Project Definition Drawings for the final lining configurations and drainage requirements for cross passages and cross passages with sumps.

Prevention of gas and water leakage at joints between cross passages and the tunnels will be of particular concern. The joints should be designed to accommodate differential movements and distortions resulting from settlements, changes in groundwater levels (from discontinuing construction dewatering and long term changes), and from seismic events.


9.0 - Building and Utility Protection Measures


9.0 BUILDING AND UTILITY PROTECTION MEASURES

By minimizing ground loss due to tunneling and excavation at station and shaft locations, damage to the buildings and utilities can be limited. The settlement criteria applicable to the project are presented in the Technical Requirements Section 31 71 19, Excavation by Tunnel Boring Machine. To meet these criteria and to demonstrate that they are met, the Design‐Build Contractor as indicated in the Construction Monitoring Program under Technical Requirements Section 31 09 13, Geotechnical Instrumentation and Monitoring is required to:

Evaluate ground movements caused by tunneling and shaft and station excavations

Determine where building and utility protection is needed

Design building protection measures

Monitor ground movements during construction to assure that the protection measures are sufficient to meet the criteria, and if necessary carry out remedial and/or additional protection measures

Perform pre‐ and post‐construction building and utility surveys to confirm that the buildings and utilities have not been damaged

9.1 Assessment of Settlements

9.1.1 Settlements caused by TBM driven Tunnels

Estimates of settlement for the tunnels have been based on: (1) ground loss due to tunneling of less than one‐half percent, (2) a settlement trough perpendicular to the tunnel resembling an inverted bell‐shaped curve, and (3) a similar settlement trough ahead of the tunnel (O’Reilly and New, 1982). Maximum settlement was estimated assuming that the volume of the settlement trough at the surface equals ground loss due to the excavation. For parallel tunnels, the effects of settlement within overlapping sections of the settlement troughs are assumed to be cumulative.

9.1.2 Settlements Adjacent to Open-Cut Construction

Estimates of the influence zone and settlements around the deep excavations have been determined following the methodology suggested by Bowles (1997) and using the historical data presented by Clough and O’Rourke (1990) and historical data taken from the MGLEE project.

Table 9-1: Impact Categories for Open-Cut Construction

Impact Category

Degree of Impact Maximum Principal Extension Strain, (%)

0 Negligible (NGL) < 0.05

1 Very Slight (VS) 0.05 to 0.075

2 Slight 0.075 to 0.15

3 Moderate 0.015 to 0.3

4 or 5 Severe to Very Severe > 0.3


May 22, 2013 Page 9-2

Geotechnical Baseline Report 9.0 – Building and Utility Protection Measures

Ground movements at the base of building have been assumed equal to the building deformation with

strains within the building structure evaluated using the deep beam theory described by Boscardin and

Cording (1989) and modified by Cording et al. (2001). The impact of the resulting strains has been

assessed using the impact categories identified in Table 9‐1.

9.2 Protection of Structures and Utilities The Design‐Build Contractor should provide additional evaluation for buildings identified on the project definition drawings identified as falling under any of the following categories: having four or more above ground stories; or having two or more basement levels; or are designated as historic or eligible historic; or have an asymmetric structural configuration (i.e., Fox Wilshire/Saban Theater at 8430/8442 Wilshire Boulevard) that could result in damage from differential settlements.

In addition to the grouting required for the protection of structures, ground treatment by means of permeation grouting with chemical or other suitable grout is the Contractor’s responsibility to improve granular soils and reduce ground loss during excavation at specified locations. These locations include major utilities, cross passage and sump structure locations, and at break‐outs and break‐ins at stations and cut‐and‐cover sections of tunnel.

As part of the program to protect buildings from the effects of tunneling, the Contractor is responsible for installing instrumentation for measuring ground movements and building settlements for (1) a demonstration section, and (2) all major structures within the zone of influence of the tunnels. The geotechnical monitoring will establish:

1. Conditions prior to tunneling or start of open cut excavations.

2. Ground movements and building settlements caused by each tunnel as it approaches and passes beyond each monitoring station.

3. Ground movements and building settlements caused by open‐cut excavation as it proceeds downwards and until the final structure is completed.

4. Confirmation that the settlement effects due to construction have ceased.

To assess actual damage resulting from tunnel construction, the Design‐Build Contractor will conduct preconstruction surveys of all private and public structures, including utilities. These surveys will include a photographic record of cracks and other pre‐existing signs of distress or damage. After tunneling has passed, the Design‐Build Contractor will re‐inspect any structure reported to have suffered damage and assess the extent of damage caused by tunnelingconstruction.

Metro will use the assessment, inspections and the geotechnical instrumentation data to assess damage to buildings from the construction activities and to monitor Contractor performance. Should observation of tunnel‐induced movements of structures indicate settlements in excess of those specified, the Contractor will be required to take appropriate action in accordance with Technical Requirements Section 31 71 16, Mined Cross Passages and Technical Requirements Section 31 71 19, Excavation by Tunnel Boring Machine.


10.0 - References


10.0 REFERENCES

10.1 Geotechnical Baseline Report References American Society for Testing and Materials, 1981, STP 741 Publication, Underground Corrosion, p69

Boduszynski , M.M., C.E. Rechsteiner, A.S.G Shafizadeh and R.M.K.Carlson, 1998, Composition and Properties of Heavy Crudes, UNITAR Center for Heavy Crude and Tar Sands.

Boscardin, M.D., and E.J. Cording, 1989, Building response to Excavated‐Induced Settlement, Journal of Geotechnical Engineering, American Society of Civil Engineers, Vol. 115, No. 1, pp 1‐21.

Bowles, J. E., “Foundation Analysis and Design”, Fifth Edition, McGraw‐Hill International Editions Civil Engineering Series, pp.803‐806, (1997)

Brown, E.T., 1981, Suggested Methods for Determining Swelling and Slake‐Durability Index Properties, Rock Characterization Testing and Monitoring, ISRM Suggested Methods, Pergamon Press

City of Los Angeles, 2004, Bureau of Engineering, Department of Public Works, Methane and Methane Buffer Zones

Clean Slurry Technology Inc., 2011, Testing of Tar Sands for Compatibility with Slurry Separation Equipment, Letter Report

Clough, G.W. and T.D. O’Rourke, “Construction Induced Movement of In‐Situ Walls”, Proceedings, Design and Performance of Earth Retaining Structures, Cornell University, American Society of Civil Engineers, Geotechnical Special Publication No. 25, pp. 439‐470, 1990.

Cording, E.J., “Impact and control of ground movement in underground construction”, Kersten Lecture, University of Minnesota, 2010

Cording, E. J., Long, J. H., Son, M., and Laefer, D. F., “Modeling and analysis of excavation‐induced building distortion and damage using a strain‐based damage criterion,” London Conference on Responses of Buildings to Excavation‐Induced Ground Movements, Imperial College, London, 2001

Hamilton D.H and R. L. Meehan, 1992, Cause of the 1985 Ross Store Explosion and Other Gas Ventings, Fairfax District, Los Angeles, Engineering Geology Practice in Southern California, Association of Engineering Geologists, Special Publication No. 4, 1992.

International Conference of Building Officials, 1988, Uniform Building Code

Keller E., and M. Crow, 2004, Tunneling through an operational oil field and active faults on the ECIS Project, Los Angeles, CA, USA. Proceedings of the North American Tunneling Conference, Atlanta, Georgia, pp 441‐448.

Kim J.S., and D.E. Crowley, 2007, Microbial diversity in natural asphalts of the Rancho La Brea Tar Pits, Applied and Environmental Microbiology, pp 4579‐91.


May 22, 2013 Page 10-2

Geotechnical Baseline Report 10.0 – References

Mendenhall, 1905, Development of Underground Waters in the Western Coastal Plain Region of Southern California, U.S. Geol Survey Water Supply Paper 139

Metro, 2010, Westside Subway Extension ‐ Final Geotechnical and Environmental Report (Advance Conceptual Engineering (ACE) phase of investigation)

Metro, 2011, Los Angeles County Transportation Authority, December 2011, Preliminary Geotechnical and Environmental Data Report

Metro, 2012a, Los Angeles County Transportation Authority, Environmental Impact Statement/ Environmental Impact Report

Metro, 2012b ‐ Los Angeles County Transportation Authority, Contract Drawings and Technical Specifications for Exploratory Shaft

Metro 2012c – Los Angeles County Transportation Authority, Geotechnical Baseline Report for Exploratory Shaft

Metro 2012d – Los Angeles County Transportation Authority, Geotechnical Data Report for Exploratory Shaft

Metro, 2012e, Los Angeles County Transportation Authority, Results of Monitoring of Gas Monitoring Wells Along the Westside Alignment from Western Avenue to the VA Hospital, Westside Subway Extension Through May 2012 (Round 2)

Metro, 2012f, Los Angeles County Transportation Authority, January 2012, Stray Current Protection Baseline Survey Report (Final)

Metro, 2012g – Los Angeles County Transportation Authority, Draft Geotechnical Baseline Report (February 2012), Regional Connector Transit Corridor Project, Contract No. E0119, prepared by The Connector Partnership

Metro, 2012h – Los Angeles County Transportation Authority, Building and Adjacent Structure Protection Report – Tunnel (Final)

Metro, 2013a, Los Angeles County Transportation Authority, Geotechnical Data Report‐Wilshire/Western Shaft

Metro, 2013b, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 ‐Wilshire/La Brea Station

Metro, 2013c, Los Angeles County Transportation Authority, Geotechnical Data Report ‐ Section 1 ‐ Wilshire/Fairfax Station

Metro, 2013d, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 ‐ Wilshire/La Cienega Station

Metro, 2013e, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 ‐ Tunnel Reach 1 (Wilshire/Western to Wilshire La Brea Station


10.0 - References


Metro, 2013f, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 ‐ Tunnel Reach 2 (Wilshire/La Brea to Wilshire Fairfax Station)

Metro, 2013g, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 ‐ Tunnel Reach 3 (Wilshire/Fairfax to Wilshire/La Cienega Station)

Metro, 2013h, Los Angeles County Transportation Authority, Geotechnical Data Report – Section 1 – Tail Track Tunnels

Metro, 2013i, Los Angeles County Transportation Authority, Environmental Data Report

Metro, 2013j, Los Angeles County Transportation Authority, Technical Geotechnical Design Memorandum – Section 1 – Tunnel Reaches 1, 2 and 3

Metro, 2013k, Los Angeles County Transportation Authority, Technical Geotechnical Design Memorandum – Section 1 – Wilshire/La Brea, Wilshire/Fairfax, Wilshire/La Cienega

Metro, 2013l, Los Angeles County Transportation Authority, Technical Geotechnical Design Memorandum – Section 1 – Tail Track Tunnels

Metro, 2013m, Los Angeles County Transportation Authority, Technical Geotechnical Design Memorandum – Section 1 – Wilshire/Western Shaft

Metro, 2013n, Los Angeles County Transportation Authority, Building and Adjacent Structure Protection Report, Cut‐and‐Cover Excavation Vol. 2 (Draft)

O’Reilly, M.P. and B.M. New, “Settlements above tunnels in the United Kingdom, their magnitude and prediction” Proceedings of Tunneling ’82, Brighton, 1982, pp. 173‐181. Report of discussion: Trans. Inst. Mining Metallurgy, Vol. 92, Section A, pp. A35‐A48, 1983.

U.S. Bureau of Reclamation, 1985, Engineering Geology Field Manual, Department of the Interior

Thewes, M. and W. Burger, 2004, Clogging Risks for TBM Drives in Clay, Tunnels and Tunneling International, pp 28‐31, June Issue.

Wahls, H.E., 1981, Tolerable Settlements of Buildings, ASCE Journal of Geotechnical Engineering, Vol. 107, No. GT11, November 1981

West, G., 1989, Rock Abrasiveness Testing for Tunneling, Technical Note, International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstract, Volume 26, No. 2, March 1989

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T

APPENDIX A GEOLOGIC PROFILE




Appendix A- Geologic Profile

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page A-1 May 22, 2013 Amendment 3 October 15, 2013

APPENDIX A GEOLOGIC PROFILE


May 22, 2013

Geotechnical Baseline Report Appendix AAppendix A- Geologic ProfileGeologic Profile

Page A-2



APPENDIX B ENGINEERING CHARACTERIZATION OF SOILS AND ROCK

LIST OF ATTACHMENTS Soil Layer Thickness Variability within Tunnel Zone – All Reaches ............................................................................................... B-1

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) – Reach 1 .................................. B-2

Composite Particle Size Distribution Chart within Tunnel Zone of Fernando Formation (Tf) – Reach 1 ....................................... B-3

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) without Asphalt – Reach 2 ......... B-4

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) with Asphalt – Reach 2 .............. B-5

Composite Particle Size Distribution Chart within Tunnel Zone of Fernando Formation (Tf) with Asphalt – Reach 2 ................... B-6

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) without Asphalt – Reach 3 ......... B-7

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) with Asphalt – Reach 3 .............. B-8

Atterberg Limits Test Results within Tunnel Zone – Reach 1 ........................................................................................................ B-9

Atterberg Limits Test Results within Tunnel Zone – Reach 2 ...................................................................................................... B-10

Atterberg Limits Test Results within Tunnel Zone – Reach 3 ...................................................................................................... B-11

Soil Layer Thickness Variability within Tunnel Zone – Tail Tracks .............................................................................................. B-12

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) – Tail Tracks ............................ B-13

Atterberg Limits Test Results within Tunnel Zone – Tail Tracks .................................................................................................. B-14

Soil Layer Thickness Variability within Tunnel Zone – Wilshire/Western Retrieval Shaft ............................................................ B-15

Composite Particle Size Distribution Chart within Tunnel Zone of Lakewood Formation (Qlw) – Wilshire/Western Retrieval Shaft

..................................................................................................................................................................................................... B-16


Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) – Wilshire/Western Retrieval Shaft

..................................................................................................................................................................................................... B-17

Composite Particle Size Distribution Chart within Tunnel Zone of Fernando Formation (Tf) – Wilshire/Western Retrieval Shaft

..................................................................................................................................................................................................... B-18

Atterberg Limits Test Results within Tunnel Zone – Wilshire/Western Retrieval Shaft ................................................................ B-19

Soil Layer Thickness Variability within Tunnel Zone – Wilshire/La Brea Station ......................................................................... B-20

Composite Particle Size Distribution Chart within Tunnel Zone of Lakewood Formation (Qlw) – Wilshire/La Brea Station ........ B-21

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) – Wilshire/La Brea Station ....... B-22

Composite Particle Size Distribution Chart within Tunnel Zone of Fernando Formation (Tf) – Wilshire/La Brea Station ............ B-23

Atterberg Limits Test Results within Tunnel Zone – Wilshire/La Brea Station ............................................................................. B-24

Soil Layer Thickness Variability within Tunnel Zone – Wilshire/Fairfax Station ........................................................................... B-25

Composite Particle Size Distribution Chart within Tunnel Zone of Quaternary Older Alluvium (Qalo) and Lakewood Formation (Qlw) without Asphalt – Wilshire/Fairfax Station .......................................................................................................................... B-26

Composite Particle Size Distribution Chart within Tunnel Zone of Quaternary Older Alluvium (Qalo) with Asphalt – Wilshire/Fairfax Station ................................................................................................................................................................ B-27

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) with Asphalt – Wilshire/Fairfax Station .......................................................................................................................................................................................... B-28

Composite Particle Size Distribution Chart within Tunnel Zone of Fernando Formation (Tf) with Asphalt – Wilshire/Fairfax Station

..................................................................................................................................................................................................... B-29

Atterberg Limits Test Results within Tunnel Zone – Wilshire/Fairfax Station .............................................................................. B-30

Soil Layer Thickness Variability within Tunnel Zone – Wilshire/La Cienega Station ................................................................... B-31

Composite Particle Size Distribution Chart within Tunnel Zone of Quaternary Older Alluvium (Qalo) and Lakewood Formation (Qlw) – Wilshire/La Cienega Station ............................................................................................................................................ B-32

Composite Particle Size Distribution Chart within Tunnel Zone of San Pedro Formation (Qsp) – Wilshire/La Cienega Station

..................................................................................................................................................................................................... B-33

Atterberg Limits Test Results within Tunnel Zone – Wilshire/La Cienega Station ....................................................................... B-34

Appendix B-1

Williamsale

Stamp

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL

GRAIN SIZE IN MILLIMETERS

medium

SANDfine

U.S. SIEVE NUMBERS HYDROMETER

6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY

U.S. SIEVE OPENING IN INCHES

4 10 20 40 100

G-302; 58.5G-302; 64.5G-302; 70.5G-302; 73.5G-303; 71.5G-304; 66.5G-306; 59.5G-306; 71.5G-306; 80.5G-307; 57.5G-307; 63.5G-307; 71.5S-101; 39S-101; 49.5S-101; 55S-101; 63S-101; 67S-102; 60S-102; 67S-102; 72.5

G-1; 70.5G-101; 49.5G-101; 54G-101; 59.5G-102; 45.5G-102; 50.5G-102; 60.5G-102; 65.5G-103; 49.5G-103; 52.5G-103; 61.5G-104; 65.5G-104; 76.5G-104; 85.5G-105; 55.5G-105; 60.5G-105; 70.5G-106; 64.5G-111; 65.5G-111; 70.5G-113; 80.5G-206; 50.5G-206; 60.5G-206; 70.5G-207; 55.5G-207; 71.5G-301; 60.5G-301; 66.5G-301; 81.5G-302; 52.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-2

jimmy.francisco

Typewritten Text

Tunnel Reach 1 Composite Plot of Particle Size Distribution for Coarse-Grained Soils within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Text Box

Mean + 1 Standard Deviation

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Line

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Text Box

Mean + 2 Standard Deviations

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Text Box

Mean

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Text Box

Mean - 1 Standard Deviation

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Mean - 2 Standard Deviations

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Typewritten Text

*Tunnel zone is taken as 10 feet above the tunnel crown to 10 feet below the tunnel invert Boring ID and Sample Depth (feet)

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-101; 29.5G-101; 39.5G-102; 30.5G-102; 35.5G-103; 40.5G-111; 50.5G-111; 80.5G-113; 50.5G-207; 51.5G-307; 49.5S-101; 33.1S-101; 44.4S-102; 56.1

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-3

jimmy.francisco

Typewritten Text

Tunnel Reach 1 Composite Plot of Particle Size Distribution for Fine-Grained Soils within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


jimmy.francisco

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Text Box

Mean

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Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-305; 111.5G-307; 83S-102; 79S-102; 87S-103A; 81S-103A; 96S-103A; 106

G-104; 90.5G-105; 80.5G-105; 95.5G-106; 81.5G-107; 75.5G-107; 85G-107; 100.5G-108; 70.5G-108; 90.5G-108; 105.5G-109; 90.5G-109; 110.5G-110; 75.5G-110; 85.5G-110; 95.5G-110; 105.5G-111; 85.5G-206; 80.5G-207; 80.5G-302; 76.5G-303; 77.5G-303; 85.5G-303; 98.5G-304; 72.5G-304; 81.5G-304; 90.5G-304; 96.5G-305; 75.5G-305; 87.5G-305; 99.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-4

jimmy.francisco

Typewritten Text

Tunnel Reach 1 Composite Plot of Particle Size Distribution for Soils within Tunnel Zone* of Fernando Formation (Tf)

jimmy.francisco

Text Box


jimmy.francisco

Text Box


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Text Box

Mean

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Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-116; 55.5G-116; 60.5G-116; 65.5G-116; 80.5G-4; 70.5S-104; 39.5S-104; 54.5S-104; 67S-104; 77S-104; 82

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-5

jimmy.francisco

Typewritten Text

Tunnel Reach 2 Composite Plot of Particle Size Distribution for Coarse-Grained Soils without Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


jimmy.francisco

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Mean

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Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-121; 65.5G-121; 70.5G-121; 95.5G-310; 70.5G-310; 82.5G-316; 67.5G-316; 73.5G-316; 79.5G-316; 91.5G-350; 35.5G-350; 60.5G-351; 45.5G-351; 55.5G-351; 75.5S-117; 39S-117; 47S-117; 55S-117; 62S-118; 72S-118; 79S-350; 36.5S-350; 46.5S-350; 57.5S-350; 69

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-6

jimmy.francisco

Typewritten Text

Tunnel Reach 2 Composite Plot of Particle Size Distribution for Coarse-Grained Soils with Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


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Mean

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Text Box


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Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-116; 50.5S-104; 44.5

Appendix B-7

jimmy.francisco

Typewritten Text

Tunnel Reach 2 Composite Plot of Particle Size Distribution for Fine-Grained Soils without Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-121; 80.5G-310; 91.5S-117; 67

Appendix B-8

jimmy.francisco

Typewritten Text

Tunnel Reach 2 Composite Plot of Particle Size Distribution for Fine-Grained Soils with Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-119; 95.5G-119; 105.5G-310; 97.5G-311; 97.5G-311; 106.5G-311; 112.5G-316; 100.5G-317; 80.5S-105; 82S-105; 96S-116; 76S-116; 81S-116; 91S-116; 101S-116; 106S-118; 84S-118; 94S-301; 93S-301; 116S-301; 130

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-9

jimmy.francisco

Typewritten Text

Tunnel Reach 2 Composite Plot of Particle Size Distribution for Soils with Asphalt within Tunnel Zone* of Fernando Formation (Tf)

jimmy.francisco

Text Box


jimmy.francisco

Text Box


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Mean

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Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

S-106; 36

Appendix B-10

jimmy.francisco

Typewritten Text

Tunnel Reach 3 Composite Plot of Particle Size Distribution for Coarse-Grained Soil with Asphalt and within Tunnel Zone* of Quaternary Older Alluvium (Qalo)

jimmy.francisco

Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-125; 59.5G-125; 77.5G-125; 90G-126; 75.5G-126; 80.5G-127; 70.5G-128; 45.5G-313; 67.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-11

jimmy.francisco

Typewritten Text

Tunnel Reach 3 Composite Plot of Particle Size Distribution for Coarse-Grained Soils without Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Typewritten Text


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Mean

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10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-124; 30.5G-124; 45.5G-124; 60.5S-106; 42S-106; 51S-106; 57S-106; 66S-106; 71.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-12

jimmy.francisco

Typewritten Text

Tunnel Reach 3 Composite Plot of Particle Size Distribution for Coarse-Grained Soils with Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

jimmy.francisco

Text Box


jimmy.francisco

Line

jimmy.francisco

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0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-125; 65.5G-126; 65.5G-127; 55.5G-127; 75.5G-128; 55.5G-128; 70.5G-313; 43.5G-313; 49.5G-313; 58.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-13

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Tunnel Reach 3 Composite Plot of Particle Size Distribution for Fine-Grained Soils without Asphalt and within Tunnel Zone* of San Pedro Formation (Qsp)

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0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Tunnel Reach 1Atterberg Limits Test Results within Tunnel Zone*

indicates Non-Plastic (NP)

Boring ID; Sample Depth (feet)

G-101; 29.5 G-101; 39.5 G-101; 44 G-102; 30.5 G-102; 35.5 G-102; 50.5 G-102; 60.5 G-103; 37.5 G-103; 40.5 G-103; 49.5

S-103A; 96 S-103A; 106

G-307; 63.5 G-307; 83 S-101; 33.1 S-101; 39 S-101; 44.4 S-102; 56.1 S-102; 72.5 S-102; 79 S-102; 87 S-103A; 81

G-303; 98.5 G-304; 72.5 G-304; 81.5 G-304; 90.5 G-304; 96.5 G-305; 75.5 G-305; 87.5 G-305; 99.5 G-305; 111.5 G-307; 49.5

G-111; 80.5 G-111; 85.5 G-113; 50.5 G-206; 80.5 G-207; 51.5 G-207; 80.5 G-302; 52.5 G-302; 76.5 G-303; 77.5 G-303; 85.5

G-108; 90.5 G-108; 105.5 G-109; 90.5 G-109; 110.5 G-110; 75.5 G-110; 85.5 G-110; 95.5 G-110; 105.5 G-111; 50.5 G-111; 65.5

G-103; 67.5 G-104; 90.5 G-105; 55.5 G-105; 80.5 G-105; 95.5 G-106; 81.5 G-107; 75.5 G-107; 85 G-107; 100.5 G-108; 70.5

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-14

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*Tunnel zone is taken as 10 feet above the tunnel crown to 10 feet below the tunnel invert

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0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)




G-116; 50.5 G-119; 95.5 G-119; 105.5 G-121; 80.5 G-310; 70.5 G-310; 82.5 G-310; 91.5 G-310; 97.5 G-311; 97.5 G-311; 106.5

S-118; 84 S-301; 93 S-301; 116 S-301; 130

G-311; 112.5 G-316; 100.5 S-105; 82 S-105; 96 S-116; 76 S-116; 81 S-116; 101 S-117; 39 S-117; 62 S-117; 67

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-15

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Line

0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)




G-124; 50.5 G-125; 65.5 G-126; 80.5 G-127; 55.5 G-128; 45.5 G-128; 55.5 G-128; 70.5 G-313; 43.5 G-313; 49.5 G-313; 58.5

S-106; 36

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-16

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2

42

3

2

1

1

4

6

8

10

12

14

16

18

20

Laye

r Thi

ckne

ss in

Fee

t

Wilshire/Western Retrieval ShaftSoil Layer Thickness Variability

4 32

3

0

2

4

CH CL

CL-

ML

MH

ML

SC

-SM SC

SM

SP-

SC

SP-

SM

SW-S

C

SW

-SM SP

SW

GC

-GM

GC

GM

GP

-GM

GW

-GC

GW

-GM GP

GW

Soil TypeSan Pedro Formation (Qsp) - Average ThicknessSan Pedro Formation (Qsp) - Minimum ThicknessSan Pedro Formation (Qsp) - Maximum ThicknessLakewood Formation (Qlw) - Average ThicknessLakewood Formation (Qlw) - Maximum ThicknessLakewood Formation (Qlw) - Minimum Thickness

Appendix B-17

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Note: Minimum, maximum, and average values shown are based on boring data where a particular soil type was encountered

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-101; 14

Appendix B-18

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Wilshire / Western Retrieval Shaft Composite Plot of Particle Size Distribution for Coarse-Grained Soil within Lakewood Formation (Qlw)

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Boring ID and Sample Depth (feet)

0

10

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30

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-101; 24G-102; 20.5

Appendix B-19

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Wilshire / Western Retrieval Shaft Composite Plot of Particle Size Distribution for Fine-Grained Soils within Lakewood Formation (Qlw)

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0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-101; 49.5G-101; 54G-101; 59.5G-101; 69.5G-102; 45.5G-102; 50.5G-102; 60.5G-102; 65.5S-101; 39S-101; 49.5S-101; 55S-101; 63S-101; 67

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-20

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Wilshire/Western Retrieval Shaft Composite Plot of Particle Size Distribution for Coarse-Grained Soils within San Pedro Formation (Qsp)

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0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-101; 29.5G-101; 39.5G-102; 30.5G-102; 35.5S-101; 19S-101; 33.1S-101; 44.4

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-21

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Wilshire/Western Retrieval Shaft Composite Plot of Particle Size Distribution for Fine-Grained Soils within San Pedro Formation (Qsp)

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0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-102; 75.5

Appendix B-22

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Wilshire/Western Retrieval Shaft Composite Plot of Particle Size Distribution for Soil within Fernando Formation (Tf)

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0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Wilshire/Western Retrieval ShaftAtterberg Limits Test Results



G-101; 29.5 G-101; 39.5 G-101; 44 G-102; 20.5 G-102; 30.5 G-102; 35.5 G-102; 50.5 G-102; 60.5 G-102; 75.5 S-101; 19

S-101; 23 S-101; 33.1 S-101; 39 S-101; 44.4 S-101; 71 S-101; 82

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-23

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7

20

2

1

12

6

15

1

11

4

2 3

25

1

1510

1

6

21

11

1 10

10

20

30

40

50

60

70

80

CH CL

ML

MH

ML

SM SC

SM SC

SM SC SM SP

SW GM

GC

GM

GM GC

GM GP

GW

SIL

TSTO

NE

Laye

r Thi

ckne

ss in

Fee

t

Wilshire/La Brea StationSoil Layer Thickness Variability

CH CL

CL-

ML

MH

ML

SC

-SM SC

SM

SP-

SC

SP-

SM

SW-S

C

SW

-SM SP

SW

GC

-GM

GC

GM

GP

-GM

GW

-GC

GW

-GM GP

GW

SIL

TSTO

NE

Soil Type

Quaternary Younger Alluvium (Qal) - Average Thickness Lakewood Formation (Qlw) - Average ThicknessLakewood Formation (Qlw) - Maximum Thickness Lakewood Formation (Qlw) - Minimum ThicknessQuaternary Older Alluvium (Qalo) - Average Thickness San Pedro Formtation (Qsp) - Average ThicknessSan Pedro Formtation (Qsp) - Maximum Thickness San Pedro Formtation (Qsp) - Minimum ThicknessFernando Formation (Tf) - Average Thickness Fernando Formation (Tf) - Maximum ThicknessFernando Formation (Tf) - Minimum Thickness

Appendix B-24

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10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-112; 40.5G-113; 20.5G-114; 39.5G-308; 15.5OB-306; 12.5OB-306; 45.5P-305; 15.5S-104; 8

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-25

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Wilshire/La Brea Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils within Lakewood Formation (Qlw)

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Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-113; 6.5G-114; 48G-3; 30.5G-308; 20.5G-308; 30.5G-309; 40.5OB-304; 20.5OB-304; 30.5OB-304; 35.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-26

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Wilshire/La Brea Station Composite Plot of Particle Size Distribution for Fine-Grained Soils within Lakewood Formation (Qlw)

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Line

0

10

20

30

40

50

60

70

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100

0.0010.010.1110100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-112; 65.5G-112; 75.5G-112; 85.5G-113; 80.5G-114; 60.5G-114; 69.5G-114; 80.5G-308; 72.5G-308; 78.5G-308; 84.5G-309; 58.5G-309; 74.5G-309; 77.5G-309; 83.5G-4; 70.5OB-304; 60.5S-104; 35S-104; 39.5S-104; 54.5S-104; 67S-104; 77S-104; 82

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-27

jimmy.francisco

Typewritten Text

Wilshire/La Brea Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils within San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


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jimmy.francisco

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Mean

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jimmy.francisco

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Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-113; 40.5G-113; 50.5G-114; 51.5G-114; 57.5G-308; 60.5S-104; 23S-104; 44.5

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-28

jimmy.francisco

Typewritten Text

Wilshire/La Brea Station Composite Plot of Particle Size Distribution for Fine-Grained Soils within San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


jimmy.francisco

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jimmy.francisco

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Mean

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Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-112; 110.5G-113; 90.5G-114; 92.5G-308; 90.5G-308; 96.5G-308; 108.5G-309; 89.5G-309; 104.5OB-304; 90.5S-104; 86S-104; 92S-104; 106.2

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-29

jimmy.francisco

Typewritten Text

Wilshire/La Brea Station Composite Plot of Particle Size Distribution for Soils within Fernando Formation (Tf)

jimmy.francisco

Text Box


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Mean

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Williamsale

Line

0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Wilshire / La Brea StaionAtterberg Limits Test Results



G-112; 40.5 G-112; 45.5 G-112; 110.5 G-113; 6.5 G-113; 30.5 G-113; 40.5 G-113; 50.5 G-113; 90.5 G-114; 19.5 G-114; 39.5

P-305; 35.5 P-305; 52.5 S-104; 17 S-104; 35 S-104; 86 S-104; 92 S-104; 101.2

G-309; 104.5 G-4; 10.5 G-4; 30.5 OB-304; 20.5 OB-304; 35.5 OB-304; 90.5 OB-306; 12.5 OB-306; 20.5 OB-306; 37.5 P-305; 15.5

G-308; 45.5 G-308; 48.5 G-308; 60.5 G-308; 90.5 G-308; 96.5 G-308; 108.5 G-309; 20.5 G-309; 40.5 G-309; 77.5 G-309; 89.5

G-114; 48 G-114; 51.5 G-114; 57.5 G-114; 92.5 G-3; 5.5 G-3; 40.5 G-3; 45.5 G-308; 15.5 G-308; 20.5 G-308; 30.5

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-30

jimmy.francisco

Rectangle

Williamsale

Line

7

22

129

3

41

22

4

11

3

5

13

7

6

10

20

30

40

50

60

70

Laye

r Thi

ckne

ss in

Fee

t

Wilshire/Fairfax StationSoil Layer Thickness Variability

112

44

5

4 113

3

3

12

7

10

10

CH CL

CL-

ML

MH

ML

SC-S

M SC

SM

SP-S

C

SP-S

M

SW

-SC

SW

-SM SP

SW

GC

-GM

GC

GM

GP-

GM

GW

-GC

GW

-GM GP

GW

SIL

TSTO

NE

Soil TypeQuaternary Younger Alluvium (Qal) - Average Thickness Lakewood Formation (Qlw) - Average ThicknessLakewood Formation (Qlw) - Maximum Thickness Lakewood Formation (Qlw) - Minimum ThicknessSan Pedro Formation (Qsp) - Average Thickness San Pedro Formation (Qsp) - Maximum ThicknessSan Pedro Formation (Qsp) - Minimum Thickness Quaternary Older Alluvium (Qalo) - Average ThicknessQuaternary Older Alluvium (Qalo) - Maximum Thickness Quaternary Older Alluvium (Qalo) - Minimum ThicknessFernando Formation (Tf) - Average Thickness Fernando Formation (Tf) - Maximum ThicknessFernando Formation (Tf) - Minimum Thickness

Appendix B-31

jimmy.francisco

Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-123; 15.5G-312; 25.5G-318; 25.5G-318; 35.5S-106; 18S-106; 21S-106; 26S-106; 36

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-32

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils with Asphalt and within Quaternary Older Alluvium (Qalo) and Lakewood Formation (Qlw)

jimmy.francisco

Text Box


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Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-318; 20.5G-350; 15.5

Appendix B-33

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Coarse-Grained Soil without Asphalt and within Lakewood Formation (Qlw)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-312; 15.5G-350; 10.5

Appendix B-34

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Fine-Grained Soils without Asphalt and within Quaternary Older Alluvium (Qalo) and Lakewood Formation (Qlw)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

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100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

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EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

S-106; 57S-106; 66S-106; 71.5S-106; 81S-106; 106S-350; 26.5S-350; 36.5S-350; 46.5S-350; 57.5S-350; 69S-350; 79S-350; 94

G-123; 44.5G-123; 55.5G-123; 69.5G-124; 15.5G-124; 30.5G-124; 45.5G-124; 60.5G-124; 80.5G-312; 38.5G-312; 43.5G-312; 58.5G-312; 85.5G-318; 75.5G-319; 40.5G-319; 55.5G-319; 80.5G-350; 25.5G-350; 35.5G-350; 60.5G-350; 80.5G-351; 45.5G-351; 55.5G-351; 75.5G-351; 95.5I-1; 20.5I-1; 45.5I-1; 65.5I-1; 85.5S-106; 42S-106; 51

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-35

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils with Asphalt and within San Pedro Formation (Qsp)

jimmy.francisco

Line

jimmy.francisco

Text Box


jimmy.francisco

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Mean

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Williamsale

Line

0

10

20

30

40

50

60

70

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100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-123; 33.5G-312; 95.5

Appendix B-36

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Fine-Grained Soils with Asphalt and within San Pedro Formation (Qsp)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-319; 90.5S-106; 117

Appendix B-37

jimmy.francisco

Typewritten Text

Wilshire/Fairfax Station Composite Plot of Particle Size Distribution for Soil with Asphalt and within Fernando Formation (Tf)

jimmy.francisco

Typewritten Text


Williamsale

Line

0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Wilshire / Fairfax StationAtterberg Limits Test Results



G-123; 20.5 G-123; 94.5 G-124; 20.5 G-124; 50.5 G-124; 85.5 G-312; 15.5 G-312; 25.5 G-312; 95.5 G-318; 15.5 G-318; 65.5

G-7; 30.5 S-106; 18 S-106; 21 S-106; 26 S-106; 36 S-106; 106 S-106; 117

G-319; 15.5 G-319; 25.5 G-319; 90.5 G-350; 10.5 G-350; 25.5 G-350; 90.5 G-5; 20.5 G-5; 30.5 G-6; 70.5 G-7; 15.5

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-38

jimmy.francisco

Rectangle

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Williamsale

Line

5

32

1

2

1

9

24

33

12

1

13

12

1

11

5 0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

Laye

r Thi

ckne

ss in

Fee

t

Wilshire/La Cienega StationSoil Layer Thickness Variability

211

1

11

11

0.0

5.0

CH CL

CL-

ML

MH

ML

SC-S

M SC

SM

SP-S

C

SP-S

M

SW

-SC

SW

-SM SP

SW

GC

-GM

GC

GM

GP

-GM

GW

-GC

GW

-GM GP

GW

Soil TypeQuaternary Younger Alluvium (Qal) - Average Thickness Quaternary Younger Alluvium (Qal) - Maximum ThicknessQuaternary Younger Alluvium (Qal) - Minimum Thickness Quaternary Older Alluvium (Qalo) - Average ThicknessSan Pedro Formation (Qsp) - Average Thickness San Pedro Formation (Qsp) - Maximum ThicknessSan Pedro Formation (Qsp) - Minimum Thickness

Appendix B-39

jimmy.francisco

Typewritten Text

Note: Minimum, maximum, and average values shown are based on boring data where a particular soil type was encountered .

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 5.5

Appendix B-40

jimmy.francisco

Typewritten Text

Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Fine-Grained Soil within Quaternary Younger Alluvium (Qal)

jimmy.francisco

Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-131; 10.5

Appendix B-41

jimmy.francisco

Typewritten Text

Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Coarse-Grained Soil within Quaternary Older Alluvium (Qalo)

jimmy.francisco

Typewritten Text


0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 15.5G-128; 25.5G-132; 25.5

Appendix B-42

jimmy.francisco

Typewritten Text

Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Fine-Grained Soils within Quaternary Older Alluvium (Qalo)

jimmy.francisco

Typewritten Text


0

10

20

30

40

50

60

70

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100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 45.5G-128; 85G-129; 34G-129; 44G-129; 59.5G-129; 64G-129; 104G-130B; 55.5G-130B; 80.5G-130B; 120.5G-131; 55.5G-131; 65.5G-131; 80.5G-131; 95.5G-132; 60.5G-132; 80.5S-107; 33.5S-107; 46S-107; 48S-107; 52S-107; 57S-107; 64S-107; 76.1

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

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Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils within San Pedro Formation (Qsp)

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10

20

30

40

50

60

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90

100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 30.5G-128; 55.5G-128; 70.5G-129; 14G-129; 24G-129; 69.5G-129; 89.5G-130B; 40.5G-130B; 60.5G-130B; 100.5G-131; 35.5G-131; 50.5G-132; 35.5G-132; 45.5G-132; 90.5G-132; 100.5S-107; 42S-107; 59S-107; 72S-107; 85

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-44

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Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Fine-Grained Soils within San Pedro Formation (Qsp)

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0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Wilshire / La Cienega StationAtterberg Limits Test Results



G-128; 5.5 G-128; 15.5 G-128; 25.5 G-128; 30.5 G-128; 35.5 G-128; 45.5 G-128; 55.5 G-128; 70.5 G-128; 80.5 G-128; 85

S-107; 18.5 S-107; 28 S-107; 33.5 S-107; 37 S-107; 42 S-107; 48 S-107; 59 S-107; 67 S-107; 72 S-107; 85

G-131; 35.5 G-131; 45.5 G-131; 65.5 G-131; 105.5 G-132; 15.5 G-132; 25.5 G-132; 35.5 G-132; 45.5 G-132; 60.5 G-132; 70.5

G-129; 104 G-130B; 5.5 G-130B; 15.5 G-130B; 25.5 G-130B; 50.5 G-130B; 60.5 G-130B; 70.5 G-130B; 75.5 G-131; 10.5 G-131; 25.5

G-128; 95.5 G-128; 100.5 G-129; 14 G-129; 24 G-129; 34 G-129; 39.5 G-129; 44 G-129; 54 G-129; 59.5 G-129; 89.5

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-45

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4

11

2

5

1

7

7

11

10

15

20

25

Laye

r Thi

ckne

ss in

Fee

t

Tail Track Tunnels West of Wilshire/La Cienega StationSoil Layer Thickness Variability within Tunnel Zone*

21

1

1

0

5

CH CL

CL-

ML

MH ML

SC-S

M SC SM

SP-S

C

SP-S

M

SW-S

C

SW-S

M SP SW

GC

-GM

GC

GM

GP-

GM

GW

-GC

GW

-GM GP

GW

Soil TypeSan Pedro Formation (Qsp) - Average Thickness San Pedro Formation (Qsp) - Minimum ThicknessSan Pedro Formation (Qsp) - Maximum Thickness

* Tunnel zone is taken as 10 feet above the tunnel crown to 10 feet below the tunnel invert

Appendix B-46

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0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 45.5G-129; 44G-129; 59.5G-129; 64G-130B; 55.5G-131; 55.5G-131; 65.5G-132; 60.5G-132; 80.5S-107; 33.5S-107; 46S-107; 48S-107; 52S-107; 57S-107; 64S-107; 76.1

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-47

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Tail Track Tunnels West of Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Coarse-Grained Soils within Tunnel Zone* of San Pedro Formation (Qsp)

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0

10

20

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40

50

60

70

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90

100

0.0010.010.1110100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

G-128; 55.5G-128; 70.5G-129; 69.5G-130B; 40.5G-130B; 60.5G-131; 35.5G-131; 50.5G-132; 45.5S-107; 42S-107; 59S-107; 72

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

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medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

40

50

60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

GRAVEL


medium

SANDfine


6 3 1.5 3/4 3/8 60 200

PE

RC

EN

T R

ET

AIN

ED

BY

WE

IGH

T

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse fine

0

10

20

30

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60

70

80

90

100

COBBLEScoarse

SILT OR CLAY


4 10 20 40 100

Appendix B-48

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Tail Track Tunnels West of Wilshire/La Cienega Station Composite Plot of Particle Size Distribution for Fine-Grained Soils within Tunnel Zone* of San Pedro Formation (Qsp)

0

10

20

30

40

50

60

PL

AS

TIC

ITY

IN

DE

X (

%)

0 10 20 30 40 50 60 70 80 90 100 110

CL-ML

LIQUID LIMIT (%)

Tail Track Tunnels West of Wilshire/La Cienega StationAtterberg Limits Test Results within Tunnel Zone*



G-128; 45.5 G-128; 55.5 G-128; 70.5 G-129; 39.5 G-129; 44 G-129; 54 G-129; 59.5 G-130B; 50.5 G-130B; 60.5 G-130B; 70.5

S-107; 42 S-107; 48 S-107; 59 S-107; 67 S-107; 72

G-130B; 75.5 G-131; 35.5 G-131; 45.5 G-131; 65.5 G-132; 45.5 G-132; 60.5 G-132; 70.5 G-8; 50.5 S-107; 33.5 S-107; 37

CL or OL CH or OH

ML or OL

CL or OL

G-101;

MH or OH

Appendix B-49

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APPENDIX C ENGINEERING PROPERTIES

Refer to Metro, 2013j for: Engineering Properties Of Principal Geologic Units ‐ Tunnel Reach 1

Engineering Properties Of Principal Geologic Units ‐ Tunnel Reach 2

Engineering Properties Of Principal Geologic Units ‐ Tunnel Reach 3

Refer to Metro, 2013l for:

Engineering Properties of Principal Geologic Units – Tail Track Tunnels

Refere to Metro, 2013m for:

Engineering Properties Of Principal Geologic Units ‐ Wilshire/Western Shaft

Refer to Metro, 2013k for:

Engineering Properties Of Principal Geologic Units ‐ Wilshire/La Brea Station

Engineering Properties Of Principal Geologic Units ‐ Wilshire/Fairfax Station

Engineering Properties Of Principal Geologic Units ‐ Wilshire/La Cienega Station

Design‐Build Contractor is responsible for reviewing the data in the Geotechnical Data Reports (Metro, 2013,a‐h), Environmental Design Report (Metro, 2013i) and the Geotechnical Design Memoranda (Metro, 2013j‐m) and developing engineering properties for the design.


APPENDIX D BASELINE SUMMARY OF CHEMICAL CONSTITUENTS IN GROUND AND GROUNDWATER

List of Tables

Table D‐1: Environment 1 (VOCs and TPH in Soil) ..................................................................................................... D‐1

Table D‐2: Environment 2 (Corrosive Soils) ............................................................................................................... D‐2

Table D‐3: Environment 3 (Methane and H2S in Soil) ............................................................................................... D‐2

Table D‐4: Environment 4 (VOCs and TPH in Groundwater) ..................................................................................... D‐3

Table D‐5: Environment 5 (Anions/Salts in Groundwater) ........................................................................................ D‐4

Table D‐6: Environment 6 (Other constituents / properties of Groundwater) ......................................................... D‐4

Table D‐7: Environment 7 (Methane and H2S in Groundwater) ............................................................................... D‐4

Explanation of Table Symbols * No test data; reported values are based on data from adjacent reaches/correlation with other soil and

bedrock properties/published data in literature, and/or based on our prior experience

** Limited data; reported values are based on data within this reach and that from adjacent reaches/correlation with other soil and bedrock properties/published data in literature, and/or based on our prior experience

“NP” indicates non‐plastic material

# Estimated using a specific gravity of 2.65 when a specific gravity test was not performed

“NA” indicates engineering property not applicable for the material type

pcf = pounds per cubic foot; psf = pounds per square foot; psi = pounds per square inch; cm = centimeter; ppm = parts per million; mg = milligrams; kg = kilograms




Appendix D - Baseline Summary of Chemical Constituents in Ground and Groundwater

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page D-1 Amendment 3 October 15, 2013 May 22, 2013

Table D-1: Environment 1 (VOCs and TPH in Soil)

Chemical of Concern

(COC)

Units

Stations Tunnels

Wilshire/La Brea

Wilshire/Fairfax

Wilshire/La Cienega

Reach 1 Reach 2 Reach 3

1,1 – dichloroethene g/kg 4.6

1,2,4-Trimethylbenzene

g/kg

9.3

31

1,3,5-Trimethylbenzene

g/kg

4.9

8.1

4-Isopropyltoluene g/kg 12.0

Benzene g/kg 8.7 4.1

Carbon Disulfide g/kg 5.9 11.0 6.2

Ethylbenzene g/kg 41 8.4

Isopropylbenzene g/kg 860

m,p-Xylene g/kg

42

MTBE g/kg 18

n-Butylbenzene g/kg

240

n-Propylbenzene g/kg

2,700

3.9

Naphthalene g/kg

31

20

o-Xylene g/kg

77

15

Sec-Butylbenzene g/kg

230

tert-Butanol g/kg 89

Toluene g/kg 6.4

TPH-GRO mg/kg

38

37

33

25

TPH-DRO mg/kg 140

65,000 140 59,000

62,000

TPH-ORO mg/kg

370

83,000

570

32

75,000

92,000

Shaded box indicates maximum concentration of COC encountered


May 22, 2013 Page D-2

Geotechnical Baseline Report Appendix D - Baseline Summary of Chemical Constituents in Ground and Groundwater

Table D-2: Environment 2 (Corrosive Soils)

Chemical of Concern

(COC)

Units

Stations Tunnels

Wilshire/La Brea

Wilshire/Fairfax

Wilshire/La Cienega


Chlorides ppm

888 2,776 142 2,20

7 2,776 2,776

Sulfates ppm

6,50

9 8,790

1,12

0 7,71

2 8,074

5,897

pH 4.6 2 2 3.1 2 2

Resistivity Ohm-cm 244

220

390

196

220

220

Shaded box indicate maximum concentration of COC as reported in TMGeotechnical Design Memorandum (Metro, 2013)

Table D-3: Environment 3 (Methane and H2S in Soil)

Chemical of Concern (COC)

Units

Stations Tunnels

Wilshire/La Brea

Wilshire/Fairfax

Wilshire/La Cienega


Methane %

0.7

98.2

39.8

1.2

91.5

98.2

Hydrogen Sulfide ppm

0.1

6,500

1.0

460

6,500



Appendix D - Baseline Summary of Chemical Constituents in Ground and Groundwater

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page D-3 Amendment 3 October 15, 2013 May 22, 2013

Table D-4: Environment 4 (VOCs and TPH in Groundwater)


Units

Stations Tunnels

Wilshire/La Brea

Wilshire/Fairfax Wilshire/La

Cienega Reach 1 Reach 2 Reach 3

1,1 – dichloroethane g/kg 0.61

1,1 – dichloroethene g/kg

0.87 2.2

Benzene g/kg 3.4

3.4

Bromodichloromethane g/kg 3.6

Bromoform g/kg 0.62

Chloroform g/kg 8.2

cis-1,2-Dichloroethene g/kg 7.6 1.5

1.8

Dibromochloromethane g/kg 0.59 2.3

MTBE g/kg 69 67

n-Propylbenzene g/kg 16

Naphthalene g/kg

24

Trichloroethene (TCE) g/kg

6.3

7.2

Toluene g/kg

10.0

8.8

14

TPH-GRO mg/kg

0.42

TPH-DRO mg/kg 1.4 5.3 0.84 1.2

TPH-ORO mg/kg

0.94

6.2

0.61

0.63



May 22, 2013 Page D-4

Geotechnical Baseline Report Appendix D - Baseline Summary of Chemical Constituents in Ground and Groundwater

Table D-5: Environment 5 (Anions/Salts in Groundwater)


Units

Stations Tunnels

Wilshire/La Brea

Wilshire/Fairfax

Wilshire/La Cienega Reach 1 Reach 2 Reach 3

Chlorides mg/L

1,800

19,000

140

110

89

Sulfates mg/L

32

270

210

68

250

Nitrates (as N) mg/L

Sulfides, total mg/L 0.18 0.7 66 7.4 0.03


Table D-6: Environment 6 (Other constituents / properties of Groundwater)


Units Stations Tunnels

Wilshire/La Brea Wilshire/Fairfax Wilshire/La Cienega Reach 1 Reach 2 Reach 3

Oil & Grease mg/L

2.4

3.3

1,4-Dioxane g/L

0.08

Hardness g/L 570 900 410 430

pH

7.2

7.1

7.0

7.1

7.2

Alkalinity, total mg/L

910

580

715

500


Table D-7: Environment 7 (Methane and H2S in Groundwater)


Units Stations Tunnels

Wilshire/La Brea Wilshire/Fairfax Wilshire/La Cienega Reach 1 Reach 2 Reach 3

Methane, Dissolved g/L

5,200

272,000

9.0

3,400

319,000

6,600

Hydrogen Sulfide, dissolved mg/L

0.7

6.5

0.06

0.005



APPENDIX E SUPPLEMENTARY DISCUSSION OF GAS MONITORING




Appendix E- Supplementary Discussion of Gas Monitoring

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page E-1 Amendment 3 October 15, 2013 May 22, 2013

APPENDIX E- SUPPLEMENTARY DISCUSSION OF GAS MONITORING

Gas Monitoring Program for WSE Section 1

For the WSE Project, a monitoring program has investigated the methane and hydrogen sulfide found in the subsurface in gaseous form as well as these gases dissolved within the groundwater. The purpose of the program is to characterize the amount of gas within the soils and the amount that would off‐gas from the groundwater during construction.

For gas vapors, the investigations included:

Routine sampling during drilling of borings from Organic Vapor Analyzer (OVA) readings taken with a photo ionization detector (PID).

Well Head Space Measurements.

Multi‐Stage Gas Monitoring Probes in which nested PVC standpipes and vapor probes were installed such that gas samples could be taken periodically at different depths within each well.

In Section 1, seventeen gas monitoring wells were installed in the ACE phase of investigation with an additional twenty four wells installed in the PE/APE phase. The well locations were chosen to identify the areas where high gas concentrations were likely to be found. Gas monitoring wells locations are indicated on drawings. Installation procedures, measurement procedures and gas monitoring records are presented in Metro, 2011.

The investigations also included sampling of dissolved gases in groundwater samples. The groundwater was taken from:

Monitoring wells with the samples were analyzed in the laboratory to determine the amount of dissolved gases within them.

BAT® groundwater monitoring system used in CPT borings. The system collects groundwater samples under controlled conditions ensuring that the in situ pressure is maintained and the samples are not contaminated. One BAT® sample was successfully collected – in CB‐101 taken near the intersection of Wilshire Boulevard and South Detroit Street. Other BAT® sampling was tried in CB‐102, CB‐103 and CB‐104 located on Wilshire Boulevard between South Ridgeley Drive and South Fairfax Avenue but was unsuccessful.

Impact of Air Contamination on Gas Measurements

Interpretation of gas measurements taken underground is made difficult by the probability of contamination of samples with air. Air can be introduced into the subsurface during many phases of a gas monitoring program ‐ during drilling, installation, development and monitoring of standpipes and gas probes. Typically air consists of: Nitrogen 78.08%; Oxygen 20.95%; Argon 0.93%; Carbon Dioxide 0.04%; and other 0.01%. Its introduction will not only alter gas concentrations but will affect the chemical composition of the gas mix as the components of air, notably oxygen react with the underground gases.


May 22, 2013 Page E-2

Geotechnical Baseline Report Appendix E - Supplementary Discussion of Gas Monitoring

Field procedures can be incorporated to minimize contamination by air but cannot fully eliminate it. This can be further aggravated by barometric pressure variations that can introduce significant quantities of air to the subsurface through open or leaking standpipes and gas probes and flush out gases. Daily barometric pressure fluctuations on the order of one to two inches of water are normal in the Los Angeles Basin and will drive the movement of air through leakage paths. The pressure typically falls during the day as the atmosphere warms and rises at night as it cools. And in this fashion, gas measurements in probe holes can be compromised.

When air is introduced into an anaerobic environment, the following processes can occur:

Oxygen Consumption: Oxygen can be consumed by the aerobic biodegradation of organic compounds that are present. Carbon dioxide is the primary by‐product of this process and methane is not generally generated.

Nitrogen Fixation: Nitrogen is converted into ammonium and various nitrites and nitrates by nitrogen fixing bacteria. Hydrogen generated by these processes is typically converted into other compounds and therefore does not persistent.

Assessing the amount of oxygen and nitrogen that may have been introduced to the underground environment by the drilling, well installation and sampling activities is difficult as these gases have different degrees of activity and their relative concentrations change over time when in contact with the subsurface gases. It is generally not feasible to add these gases to the individual gas probe readings based on measured oxygen levels(assuming atmospheric proportions) since the oxygen is generally consumed preferentially before the nitrogen. The time required for these processes to run to completion is dependent on the amount of air introduced to the subsurface, the amount of organic matter present, soil chemistry and the bacteriological environment. In a typical anaerobic setting, the amount of time required for a system to recover could range from a few weeks to several months.

For gas probe readings, when oxygen is present, the sum of concentrations of oxygen, carbon dioxide and methane is typically below 100 percent. Nitrogen and argon are not accounted for in these totals and will typically make up the remainder.

For gas probe readings, when oxygen is not present or present in only low concentrations, the sum of concentrations of oxygen, carbon dioxide and methane typically approaches 100 percent. Where they do not, it is likely that nitrogen and argon are present at ratios in excess of normal atmospheric ratios (relative to oxygen).

Nitrogen, carbon dioxide and argon likely account for the balance of the gas that is “missing” in the monitoring result totals.

Impact of Asphalt on Gas Measurements

Gas monitoring in wells and probes has been adversely impacted by the asphalt from the asphalt impacted soils. A summary of the standpipes where asphalt was encountered is provided in Table 1. The impacts have included:

Clogging of Well screens – In monitoring wells installed in the early phase of the investigation, screens placed in the asphalt impacted soils clogged with oil and asphalt. To avoid this, screens installed in




monitoring wells installed between South Ridgeley Drive and Fairfax Avenue (zone of asphalt impacted soils) were placed in soils below the asphalt impacted soils (e.g., at M‐113).

Unsuccessful sampling of groundwater in CPTs ‐ BAT® sampling of groundwater (for analysis of dissolved gases) proved unsuccessful in three out of four holes in which the system was tried. The failure to obtain samples was apparently caused by asphalt from the asphalt‐impacted soils smearing the porous filter membrane of the CPT as it was driven into the ground. This asphalt smear impeded flow through the filter membrane into the BAT® sampler to such an extent that water samples were not be recovered.

Seeps of Asphalt‐Water at Ground Surface from Standpipes ‐ Asphalt has filled or partially filled seventeen standpipes installed along the Wilshire Boulevard. At five locations, the standpipes were completely filled and asphalt would seep out of standpipes when they were uncapped. At other installations (G‐7A & M‐12; and S‐3450 at Exploratory Shaft), asphalt forced its way up the borehole past the well seal, emerging at the ground surface. The condition at top of Boring S‐350 (see Figure E‐1 for Location) following discovery of the seepage and its subsequent clean‐up is shown in Figure E‐1 and E‐2.

Figure E-1


May 22, 2013 Page E-4

Geotechnical Baseline Report Appendix E - Supplementary Discussion of Gas Monitoring

Figure E-2 Figure E-3

Possible explanations for this phenomenon include:

1) Screened section of the standpipe intercepting a zone of trapped gas or an active zone of gas seepage such that the gas enters and vents through the standpipe.

2) Screened section of the standpipe intercepting a zone of asphalt impacted soil at depth that is saturated with fluid (water‐asphalt mix) in which gas is dissolved. The water‐asphalt mix enters the standpipe under hydrostatic pressure. As the fluid enters and rises up the standpipe, the confining pressure drops and the gases evolve. The evolving gas would reduce the effective density of the fluid within the standpipe. This reduces the hydrostatic pressure at the bottom of the standpipe and induces flow of the water‐asphalt‐gas mix up the standpipe resulting in it overflowing the standpipe.






APPENDIX F LOS ANGELES TUNNELING EXPERIENCE




APPENDIX G GLOSSARY OF TERMS


Page G-2



Appendix G - Glossary Of Terms

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page G-1 Amendment 3 October 15, 2013

APPENDIX G - GLOSSARY OF TERMS

Grain Size Distributions

Predominantly fine‐grained soils (as indicated on the Geologic Profile in Appendix A) consist of layers and lenses of fine grained soils with a minor number of layers and lenses of material that are coarse grained soils.

Predominantly coarse‐grained soils (as indicated on the Geologic Profile in Appendix A) consist of layers and lenses of coarse grained soils with a minor number of layers and lenses of material that are fine grained soils.

Cobbles are defined as particles between 3 and 12 inches

Boulders are defined as particles with a principle dimension greater than 12” or that will not pass through a 12‐inch square opening.

Relative Density of Soils

Based on AASHTO, 1988, the relative density of the soil profile has been determined based on blow counts from the Standard Penetration Tests (SPT).

For the fine grained materials, the soils are described as follows:

Very soft – SPT blow counts per foot ranging from 0 to 2

Soft to medium stiff ‐ SPT blow counts per foot ranging from 3 to 8

Medium to stiff – SPT blow counts per foot ranging from 9 to 16

Very stiff to hard ‐ SPT blow counts ranging from 16 to 60.

For the coarse‐grained materials, the soils are identified as follows:

Very loose to loose ‐ SPT blow counts per foot ranging from 0 to 10

Medium dense ‐ SPT blow counts per foot ranging from 11 to 30

Dense ‐ SPT blow counts per foot range from 31 to 50

Very dense ‐ SPT blow counts per foot greater than 50


Geotechnical Baseline Report Appendix G - Glossary Of Terms

Page G-2

Strength Descriptors for Intact Rock

Description Recognition Uniaxial compressive strength

estimate (psi)

Extremely weak rock Can be indented by thumbnail 35 – 150

Very weak rock Can be peeled by pocket knife 150 – 700

Weak rock Can be peeled with difficulty by pocket knife 700 – 3,600

Moderately strong rock Can be indented 1-3 mm with sharp end of pick 3,600 – 7,200

Strong rock Requires one geologic hammer blow to fracture 7,200 – 14,500

Very strong rock Requires many geologic hammer blows to fracture 14,500 – 36,000

Artesian groundwater indicates the hydraulic head is higher than elevation of the groundwater table.

Asphalt impacted soil (synonyms include: hydrocarbon impacted soil, tar sand) is material that is impregnated with naturally occurring hydrocarbons. It includes petroliferous clays and tar sands, which may refer to tar impacted materials that do not fit the description of sand (clays, silts, gravels, etc.). The Geotechnical Data Reports have used the term tar impacted soils to refer to the same materials.

Asphalt seeps or tar seeps are seepages at the ground surface of a mixture of asphalt (tar) and groundwater. They are often formed as a result of a columnar or linear feature in the soils and bedrock providing a path for upward migration of fluids. Gasses (methane and hydrogen sulfide) may be released at the seepage.

Bedrock is defined for the WSE Section 1 as the Fernando Formation.

Biogenic (meaning “coming from plants or animals”) refers to the origin of hydrogen sulfide and methane gasses produced by microorganisms consuming hydrocarbons in upper deposits.

Dynamic viscosity (μ) is a measure of the ratio of the stress on a region of a fluid to the rate of change of strain it undergoes.

Groundwater table is the level within the subsurface soils below which the soils are saturated with groundwater (Note: see Artesian groundwater and Perched groundwater).

Holocene is a geologic epoch extending from about 11,000 years ago to the present.

Kinematic viscosity (ν) is a measure of the resistance to flow of a fluid and is equal to its dynamic viscosity divided by its density (μ/ρ)

Leaky Underground Storage Tank (LUST) is a program run by the United States Environmental Protection Agency to track, monitor and remediate underground storage tanks

Miocene is a geologic epoch extending from about 23 million years ago to 5 million years ago.


Appendix G - Glossary Of Terms

W E S T S I D E S U B W A Y E X T E N S I O N P R O J E C T Page G-3 Amendment 3 October 15, 2013

Paleontological Zone (“Paleo Zone”) is a zone of soils extending from the top of undisturbed material down to the bottom of the Quartenary soils in areas where paleontological resources have been preserved. This is generally associated with zones within asphalt impacted soils but can also extend into zones not impacted by asphalt. A paleontologist observer will be on site to identify the “Paleo Zone”. Special excavation methods are required in this zone.

Perched groundwater indicates where groundwater is found in more permeable materials. The underlying less permeable materials remain fully saturated and are under a hydraulic head at least equal to the depth below the groundwater table.

Pliocene is a geologic epoch extending from about 5 million years ago to 2.5 million years ago.

Pleistocene is a geologic epoch extending from about 2.5 million years ago to 11,000 years ago.

Quartenary is a geologic period extending from 2.5 million years ago to the present.

Spills, Leaks, Investigation and Cleanup (SLIC) is a program run by the California State Environmental Protection Agency Los Angeles Regional Water Quality Control Board to track, monitor, and remediate ground and groundwater contamination. Renamed Site Cleanup Program (SCP).

Thermogenic (meaning, “coming from heat”) refers to the origin of hydrogen sulfide and methane gasses produced by heat and pressure applied to hydrocarbons in deep deposits.

Abandoned, Idle, Orphan Oil Well Oil Well Status:

Active – An oil well is considered active if it has produced oil or gas or been used for fluid injection for six consecutive months in the last five years.

Idle – An oil well is considered idle if it has not produced oil or gas or been used for fluid injection for six consecutive months in the last five years. The California State Department of Conservation Division of Oil, Gas and Geothermal Resources (DOGGR), encourages operators to either reactivate or plug and abandon idle wells.

Abandoned – An oil well is considered abandoned if it has not been properly plugged per the proper procedure at the time of abandonment.

Orphaned – An oil well is considered orphaned if it has been left idle but not properly abandoned or is leaking and has no viable operator or owner.

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