Page 1 of 5 Bolton & Menk, Inc. 2638 Shadow Lane, Suite 200 Chaska, MN 55318 Ph. (952)448-8838 Fax (952)448-8805 ADDENDUM NO. 1 FOR PROJECT: CR 110 CONSTRUCTION – WACONIA SCHOOL PHASE S.P. 1002-109, S.A.P. 231-124-001, S.A.P. 010-610-051, S.A.P. 010-610-052, DATED: MARCH 28, 2017 OWNER: CARVER COUNTY TO ALL BIDDERS: This Addendum is added to and shall become a part of the above referenced Contract Documents dated March 13, 2017. Any bids received by the Owner that do not bear the proper acknowledgement of receipt through BidVault of this Addendum 1 will not be considered. NOTE: THE BID DATE HAS NOT BEEN CHANGED THE BID DATE IS: APRIL 6, 2017 THE BID TIME HAS NOT BEEN CHANGED THE BID TIME IS: 10:00 AM The Contract Documents for the referenced project have been revised as follows: GENERAL Addendum 1 makes the following general changes to the CR 110-CSAH 10, Segment 2 plan set only (TH 5 and CSAH 10, Segment 1 plan set remains the same in its entirety): 1. Muck Excavation with material replacement of Select Granular Super Sand has been removed and replaced with a Surcharge design using a staged process. 2. The storm sewer design between STA: 141+00 to 160+00 has been offset to be constructed within the west ditch compared to be directly under the CR 110/CSAH 10 roadway. 3. Right-of-way access updates 4. Further information and clarification in regards to achieving an earthwork site balance through existing project areas, property contacts and construction timelines. 5. Driveway re-aligning at STA: 152+00. 6. Site clearing and driveway removal of Parcel ID 090220720 that the County will own during project construction. 7. Adding additional erosion control measures in between STA: 117+50 to 126+00 and STA: 155+00 to 160+00. 8. Including the document in Appendix C “Geotechnical Evaluation Report for CSAH 10 West Ring Road Segment II”.
Transcript
Page 1 of 5
Bolton & Menk, Inc. 2638 Shadow Lane, Suite 200 Chaska, MN 55318 Ph. (952)448-8838 Fax (952)448-8805
ADDENDUM NO. 1 FOR PROJECT: CR 110 CONSTRUCTION – WACONIA SCHOOL PHASE
TO ALL BIDDERS: This Addendum is added to and shall become a part of the above referenced Contract Documents dated March 13, 2017. Any bids received by the Owner that do not bear the proper acknowledgement of receipt through BidVault of this Addendum 1 will not be considered.
NOTE: THE BID DATE HAS NOT BEEN CHANGED THE BID DATE IS: APRIL 6, 2017 THE BID TIME HAS NOT BEEN CHANGED THE BID TIME IS: 10:00 AM
The Contract Documents for the referenced project have been revised as follows: GENERAL Addendum 1 makes the following general changes to the CR 110-CSAH 10, Segment 2 plan set only (TH 5 and CSAH 10, Segment 1 plan set remains the same in its entirety):
1. Muck Excavation with material replacement of Select Granular Super Sand has been removed and replaced with a Surcharge design using a staged process.
2. The storm sewer design between STA: 141+00 to 160+00 has been offset to be constructed within the west ditch compared to be directly under the CR 110/CSAH 10 roadway.
3. Right-of-way access updates 4. Further information and clarification in regards to achieving an earthwork site balance
through existing project areas, property contacts and construction timelines. 5. Driveway re-aligning at STA: 152+00. 6. Site clearing and driveway removal of Parcel ID 090220720 that the County will own during
project construction. 7. Adding additional erosion control measures in between STA: 117+50 to 126+00 and STA:
155+00 to 160+00. 8. Including the document in Appendix C “Geotechnical Evaluation Report for CSAH 10 West
Ring Road Segment II”.
Page 2 of 5
SPECIFICATIONS—CR 110 CONSTRUCTION CONTACT INFORMATION
1. ADD the following contact information: “-Surcharge questions can be directed to Bryan Field with Braun Intertec at
612.369.3210, [email protected].” EARTHWORK BALANCE INFORMATION AND CONTACTS
1. ADD this new section in Division S to add further information in regards to achieving an earthwork site balance.
(1806) DETERMINATION AND EXTENSION OF CONTRACT TIME
1. DELETE Section S-39.2 in its entirety and REPLACE with the following: Contractor has three substantial completion dates, with a final completion date, on
this project. One for the stage 1 completion of the surcharge process with instrumentation and wick drains in place, one for all of the project area south of Community Drive and one for all of the project area north of Community Drive.
See below for details on the substantial completion dates all areas and work that shall apply:
1. July 31, 2017 – Stage 1 completion of the surcharge process with instrumentation and wick drains in place: The stage 1 completion of the surcharge process including placement of select granular embankment special, settlement plates, wick drains and the vibrating wire piezometers shall be completed and ready to be monitored and recorded.
2. September 1, 2017 - All areas of the project south of Community Drive: The
CSAH 10 and Orchard Rd roadways and all connecting side streets (TH 5, 94th St. and Community Drive) shall be completed and open to traffic by September 1, 2017. This shall include the TH 5/CSAH 10 Roundabout, the 94th St intersection, Community Dr./CSAH 10 Roundabout, Ponds A-C, watermain and storm sewer south of Community Dr, final bituminous wearing course, roadway striping, and signage. Sidewalks and trails, along with final turf establishment, do not need to be completed but construction activities shall not impede on traffic operations. The Segment 1 (TH 5) roadway detour/closure between Oak Ave and CSAH 51 may not be put under full closure until June 5, 2017 and may not be under closure after September 1, 2017.
3. August 31, 2018 - CSAH 10/Waconia Pkwy S Roundabout: The CSAH
10/Waconia Pkwy S Roundabout and all connecting legs (Waconia Pkwy S, CSAH 32, and Sterling Rd) along the existing CSAH 10 shall be completed and open to traffic by August 31, 2018. This shall include the Waconia Pkwy S/CSAH 10 Roundabout, the CSAH 10/CSAH 32 intersection, the CSAH 10/Sterling Rd intersection, watermain and storm sewer north of Community Dr., final bituminous wearing course, fog seal, roadway striping, and signage. Sidewalks and trails, along with the final turf
Page 3 of 5
establishment, the pedestrian bridge and the retaining walls, do not need to be completed but construction activities shall not impede on traffic operations. The contractor may keep the CSAH 10 roadway section between Community Dr. and CSAH 10/Waconia Pkwy S closed until the final project completion date. The Segment 2 (CSAH 10) roadway detour/closure between Pond Ln and CSAH 32 may not be put under full closure until June 8, 2018 and may not be under closure after August 31, 2018.
The final completion date, in which all work under this contract must be completed, except maintenance work and Final Clean Up, will be November 15, 2018. (1807) FAILURE TO COMPLETE THE WORK ON TIME
1. DELETE Section S-40.1 in its entirety and REPLACE with the following:
The Department will assess the Contractor a monetary deduction in an amount equal to $500.00 for each Calendar Day that any of the work under the first substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions remains incomplete after the expiration of the working period provided therefore. If the contractor does not meet the second substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess a monetary deduction in an amount equal to $5,000.00. If the contractor does not meet the third substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess a monetary deduction in an amount equal to $1,500.00. Failure to complete the final completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess an addition monetary deduction (on top of the substantial completion date criteria) in an amount equal to $1,500.00.
(2011) AS-BUILTS
For clarification, this bid item is only needed within the Segment 1 area, in and adjacent to the MnDOT Right-of-Way. As-Builts according to these specifications are not required in the Segment 2 area.
(2105) GEOTEXTILE FABRIC TYPE V ADD this new section in Division S as it is a new bid item in the plan set.
(2105) PIEZOMETER
ADD this new section in Division S as it is a new bid item in the plan set. (2105) SETTLEMENT PLATES
DELETE this section in its entirety and REPLACE with the new write up section. (2105) WICK DRAINS
ADD this new section in Division S as it is a new bid item in the plan set.
Page 4 of 5
(2106) COMMON EMBANKMENT SPECIAL (CV)
ADD this new section in Division S as it is a new bid item in the plan set. (2106) SELECT GRANULAR EMBANKMENT SPECIAL (CV)
ADD this new section in Division S as it is a new bid item in the plan set. (1404) MAINTENANCE OF TRAFFIC AND (2563) TRAFFIC CONTROL
1. ADD this new heading and two paragraphs between headings S-18.6 and S-18.7:
LOCAL ACCESS AND MAINTENANCE Access to local streets and individual properties fronting or requiring access from TH 5,
CSAH 10, Orchard Rd, 94th St, or Community Dr. shall be maintained on inplace, temporary, or permanent roadway, or by an alternate access. Driveways and local streets to remain open are identified in the Plans. Closure of the local roadways identified on the Plans to remain open shall not be permitted. Closure of the driveways identified on the Plans to remain open shall only be permitted if an alternate drive or access is available or constructed and the alternate access is agreed to by the property owner. If alternate access cannot be provided, paving of these driveways shall be staged to construct the new driveway before the existing driveway is removed, or the work must be staged to construct half the driveway at a time while maintaining access.
Local access and maintenance of gravel roadways that are impacted per construction closures and detours included in the 2563 Traffic Control bit item will consist of 102nd St., Oak Ave, 78th St, and Paul Ave. Grading roadways may be needed to property apply the calcium chloride solution and/or correct road surfaces from additional traffic caused by construction activity. Grading/correcting/smoothing of these roadways is incidental but any additional labor to other tasks, equipment or materials needed per engineer’s orders will be made as Extra Work.
BID FORMS T.H. 5 AND C.S.A.H. 10, SEGMENT 1 AND C.R. 110-C.S.A.H. 10, SEGMENT 2
REMOVE the three pages of the T.H. 5 and C.S.A.H. 10, SEGMENT 1 bid form and the four pages of the C.R. 110-C.S.A.H. 10, SEGMENT 2 bid form within the bid form and contract section in the specification book. This eliminates confusion between which bid forms to use. BID FORMS SHALL ONLY BE COMPLETED ON BIDVAULT. The C.R. 110-C.S.A.H. 10, SEGMENT 2 bid form has been updated in BidVault per this Addendum.
APPENDIX C-SOILS INVESTIGATION
INSERT the “Geotechnical Evaluation Report for CSAH 10 West Ring Road Segment 2” into Appendix C.
Page 5 of 5
PLANS-- CR 110 CONSTRUCTION 1. DELETE the following sheets in their entirety and REPLACE with the included sheets of
the same name and number with revision date 3/24/17 identified on each sheet. 1, 3-6, 7-10, 12-13, 15, 44, 53-55, 58, 60-62, 73-75, 93-95, 100, 102-103, 105-111, 113-114, 121, 126-129 and 134. (44 sheets in total)
2. ADD the following sheets in their entirety and they shall become part of the construction
plan set. The plan set now contains 269 plan sheets. 6A, 44A, 44B, 44C, and 115A. (5 sheets in total)
3. DELETE the following XS sheets in their entirety and REPLACE with the included sheets
of the same name and number with revision date 3/28/17 identified on each sheet. XS1, XS19-XS34. (17 sheets in total)
END ADDENDUM 1
DIVISION S-ADDENDUM 1
CONTACT INFORMATION REVISED 3/24/16 SP2016-1
-Direct general and design questions about this Project, including pre-bid questions, can be directed to Derek Arens at 612.655.1546, [email protected].
-Structural questions can be directed to Jim Archer at 612.205.5160, [email protected]. -Pre-Fabricated Pedestrian Bridge questions can be directed to Jake Vogel at CONTECH
Engineered Solutions at 612.352.7944, [email protected]. -Surcharge questions can be directed to Bryan Field with Braun Intertec at 612.369.3210,
EARTHWORK BALANCE INFORMATION AND CONTACTS It is the Contractors sole responsibility to review the earthwork needs of the project and compile a
plan for efficient movement of the materials. Information is being provided for the benefit of the Contractor to better understand options that may be available under certain conditions to dispose of or to obtain common earthwork during the project in accordance with the price bid for each respective earthwork bid item in the contract. It shall be understood that no specific payment is being made for submittals, or terms required for use of these sites unless specifically stated herein. Information is being provided to inform the Contractor of potential options that will aid in earthwork management to reduce imports or exports of common materials. No certainty is provided that imports and exports of common or borrow materials will not be required as a result of the Contractors preferred earthwork management plan and management of site materials during the project.
The following listings may be contacted in regards to earthwork material: 1.
Pine Products Inc. 11780 County Rd 32 Waconia, MN 55387 Phone: 952-442-5988
They have inquired about possible topsoil material for purchase.
2.
ISD 110 The direct contact does not wish to be contacted but the following opportunities apply:
ID # 750270200 is a parcel owned by ISD 110 subject to prior discussions on earthwork disposal
for suitable and unsuitable grading material with the understandings that certain end conditions will be met for a final restoration of the site after use by the Contractor. The site will provide the Contractor with an opportunity to obtain material and place excess material from the CSAH 10 project if approval conditions are met for the ISD 110
use of the site. The expectations will include but may not be limited to a complete restoration of the site with erosion control in accordance with project permitting requirements, seeding and turf establishment, topsoil
placement at a minimum of 6” thick free from rocks or debris, and an approximate grading grade placed on the site that aligns towards (but not to any specific designed plan at this time) with future concepts for the site of athletic
fields. The use of the site will require the terms be met listed in this section and a submittal of a grading plan along with an earthwork management explanation of how the site will be used for borrow or fill purposes, type of
materials to be used or obtained, quantity of each, schedule, and full restoration plans. The contact for this site if the Contractor elects to utilize this area in their earthwork management effort for the CSAH 10 project is Dan Lonnes,
Bolton & Menk at 612-756-2693.
Per the Earthwork and Construction Staging Plan sheet in the Segment 2 plan set, there are areas that are
flexible to try and accomplish the earthwork balance on site: (ID 090220700) 1715 Waconia Pkwy S – The County will own this property per the timeline
stated in the plans. Stipulations of the property include protecting septic mound and drain field, electric poles, wells, propane tanks, communications lines, etc. to maintain living functional conditions of Building D if the tenant is still present. The County is attempting to relocate this tenant May 2, 2017 but the tenant has the right to be present until September 1, 2017. Buildings C and E will be demolished (by others) immediately following the May 2, 2017 acquisition.
Earthwork excavation is available (but not needed for finished grading requirements) on this site for surcharge fill material as a means to borrow suitable or unsuitable fill materials. Expected material that may be accessible while the tenant remains in-place is between 10,000-20,000 cu yd of material (prior to home removal) and with house removal is between 20,000-35,000 cu yd. If the contractor chooses to excavate this property, a contour/grading plan shall be submitted to the engineer prior to work. Final grading slopes following completion of the project cannot be any steeper than a 1:6. Material can be available to the Contractor in this area through submittal of a grading plan to the Engineer. This grading plan must comply with the terms of maintaining access to the homeowner, and maintaining stable and acceptably safe slopes as approved by the Engineer. No assurance of material quality or volume available is made herein as it is at the discretion and independent review of the Contractor to utilize this site and area in accordance with their earthwork management activities. Use of the site for borrow and fill material is contingent on an Engineer approved material borrow site grading plan that is fully restored to a 6:1 max slope prior to completion of the project.
(ID 090220720) 1715 Waconia Pkwy S Agricultural Parcel – The County will have a Right-of-
Access to this property only in non-agricultural areas (vegetative overgrown area adjacent to parcel 090220700 1715 Waconia Pkwy S) and the Temporary Easement and Proposed Right-of-Way shown on the plan. The contractor can choose to excavate but will need to submit a contour/grading plan to the engineer prior to work. Any SWPPP requirements and any other regulations in the project area that the contractor will need to meet will be incidental. Final grading slopes following completion of the project cannot be any steeper than a 1:6.
(ID 090220400) Agricultural Parcel –This parcel, which has the surcharge soil correction within it, can be graded as needed per certain construction stages. If the Contractor chooses to modify existing contours, a contour/grading plan will need to be submitted to the engineer prior to work. Any SWPPP requirements and any other regulations in the project area that the contractor will need to meet will be incidental. Final grading slopes following completion of the project cannot be any steeper than a 1:6. In addition, to these parcels, nearby property owners have inquired about possible topsoil material for purchase but not to any major extent. One property owner in particular is parcel ID 090271700. Release of electronic design files for calculations of earthwork for bidding purposes may be available upon request through [email protected]. A release form with a written signature of the “USER” will be needed prior to sending of any digital data.
(1806) DETERMINATION AND EXTENSION OF CONTRACT TIME REVISED 3/27/17 SP2016-50-MODIFIED
The Department will determine Contract Time in accordance with the provisions of MnDOT l806 and the following: S-1.1 Contractor must start construction operations by May 1, 2017 or no later than eight (8) Calendar days after the date of Notice Contract Approval, whichever is later. Contractor must not begin construction operations before contract approval.
S-1.2 Contractor has three substantial completion dates, with a final completion date, on this project. One for the stage 1 completion of the surcharge process with instrumentation and wick drains in place, one for all of the project area south of Community Drive and one for all of the project area north of Community Drive. See below for details on the substantial completion dates all areas and work that shall apply:
1. July 31, 2017 – Stage 1 completion of the surcharge process with instrumentation and wick
drains in place: The stage 1 completion of the surcharge process including placement of select granular embankment special, settlement plates, wick drains and the vibrating wire piezometers shall be completed and ready to be monitored and recorded.
2. September 1, 2017 - All areas of the project south of Community Drive: The CSAH 10 and
Orchard Rd roadways and all connecting side streets (TH 5, 94th St. and Community Drive) shall be completed and open to traffic by September 1, 2017. This shall include the TH 5/CSAH 10 Roundabout, the 94th St intersection, Community Dr./CSAH 10 Roundabout, Ponds A-C, watermain and storm sewer south of Community Dr, final bituminous wearing course, roadway striping, and signage. Sidewalks and trails, along with final turf establishment, do not need to be completed but construction activities shall not impede on traffic operations. The Segment 1 (TH 5) roadway detour/closure between Oak Ave and CSAH 51 may not be put under full closure until June 5, 2017 and may not be under closure after September 1, 2017.
3. August 31, 2018 - CSAH 10/Waconia Pkwy S Roundabout: The CSAH 10/Waconia Pkwy S
Roundabout and all connecting legs (Waconia Pkwy S, CSAH 32, and Sterling Rd) along the existing CSAH 10 shall be completed and open to traffic by August 31, 2018. This shall include the Waconia Pkwy S/CSAH 10 Roundabout, the CSAH 10/CSAH 32 intersection, the CSAH 10/Sterling Rd intersection, watermain and storm sewer north of Community Dr., final bituminous wearing course, fog seal, roadway striping, and signage. Sidewalks and trails, along with the final turf establishment, the pedestrian bridge and the retaining walls, do not need to be completed but construction activities shall not impede on traffic operations. The contractor may keep the CSAH 10 roadway section between Community Dr. and CSAH 10/Waconia Pkwy S closed until the final project completion date. The Segment 2 (CSAH 10) roadway detour/closure between Pond Ln and CSAH 32 may not be put under full closure until June 8, 2018 and may not be under closure after August 31, 2018.
The final completion date, in which all work under this contract must be completed, except maintenance work and Final Clean Up, will be November 15, 2018. S-1.3 Construction operations involving construction field work or work that impacts, restricts, or interferes with traffic as determined by the Engineer shall not commence prior to NTP2 without written permission from the Engineer. S-1.4 The Contractor must not perform work that will restrict or interfere with traffic between 12:00 noon on the day before and 9:00 A.M. on the day after any consecutive combination of a Saturday, Sunday, and legal holiday. The Contractor may request exceptions to this requirement. Exceptions must be approved in writing by the Engineer.
(A) If the Contractor chooses not to work at all on the day before the holiday period, then the Department will not assess working day charges. (B) If the Contractor chooses to work before 12:00 noon on the day before the holiday period (or later than 12:00 noon if approved by the Engineer), then the Department will assess working day charges only for the actual hours worked.
S-1.5 The following language is deleted from MnDOT 1806.3: "(3) During the inclusive period from November 15 through April 15, except as specified in 1806.1, “Determination and Extension of Contract Time, General.”". S-1.6 When, in the opinion of the Engineer, the Contractor cannot perform work on the Project due to failure of material delivery beyond the control of the Contractor, the Engineer will agree to suspend Work in conformance with MnDOT 1803.6, or will cease the charging of working days, as determined by the Engineer.
The Engineer will issue a Resumption of Work Order, or resume the charging of working days, after the Contractor has received delivery of the required material.
(1807) FAILURE TO COMPLETE THE WORK ON TIME REVISED 03/27/17 SP2016-52
The provisions of MnDOT 1807 are supplemented as follows: S-1.7 The Department will assess the Contractor a monetary deduction in an amount equal to $500.00 for each Calendar Day that any of the work under the first substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions remains incomplete after the expiration of the working period provided therefore. If the contractor does not meet the second substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess a monetary deduction in an amount equal to $5,000.00. If the contractor does not meet the third substantial completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess a monetary deduction in an amount equal to $1,500.00. Failure to complete the final completion date specified in Section S-1806.2 (DETERMINATION AND EXTENSION OF CONTRACT TIME) of these Special Provisions, the Department will assess an addition monetary deduction (on top of the substantial completion date criteria) in an amount equal to $1,500.00. S-1.8 The Department may reduce the daily liquidated damages to $100.00 when the only remaining items are maintenance or Final Cleanup. S-1.9 For informational purposes only, bidders are advised that in addition to the requirements of MnDOT 1807, other Sections of these Special Provisions, as shown below, contain requirements for assessment of monetary deductions to this Contract:
1404 MAINTENANCE OF TRAFFIC AND (2563) TRAFFIC CONTROL
1706 EMPLOYEE HEALTH AND WELFARE
2331 BITUMINOUS PAVEMENT CRACK TREATMENT CLEAN AND SEAL
2563 PORTABLE CHANGEABLE MESSAGE SIGN
2580 INTERIM PAVEMENT MARKING
S-1.10 The liquidated damages set forth in MnDOT 1807 and any monetary deductions as set forth above may apply equally, separately, and may be assessed concurrently.
(2105) GEOTEXTILE FABRIC TYPE V This work shall consist of placing geotextile fabric underneath the surcharge select granular embankment special. The work shall be accomplished according to MnDOT 2105, these Special Provisions, or as directed by the Engineer. S-1.11 MATERIAL REQUIREMENTS Geotextile shall conform to the requirements of MnDOT 3733, Type V.
S-1.12 CONSTRUCTION REQUIREMENTS The prepared surface shall be relatively smooth and free of stones, sticks, or other debris or irregularities that would tend to puncture or tear the geotextile. Unless otherwise directed or approved by the Engineer, the geotextile shall be placed with the highest strength direction (usually the "machine" or roll direction) oriented in the direction of the greatest expected field stress. For this scenario, the fabric shall be placed perpendicular to the direction of the alignments. The fabric mat should be extended the length of the surcharge alignment plus an additional 15 feet beyond either end along with 5 feet beyond the toes of the embankment slope longitudinally. If multiple pieces of geotextile are required, adjacent strips shall be field or factory sewn, with the seams to have a strength as specified in MnDOT 3733.2B. All seams shall be sewn using a "double spool" machine capable of sewing a Federal Type 401 locking stitch. Seam type (flat, "J", or butterfly), thread strength (25 pound [110 Newtons] minimum), number of rows of stitching (1 or 2) and stitches per inch [25 mm] (typically 5-7), shall be consistent with achieving the required seam strength and as recommended by the geotextile manufacturer. Overlapping of edges, without sewing, will not be allowed as separation of the fabric could occur during placement of the fill and during the consolidation process. During installation, the fabric may only be extended only several strip widths (no more than 50 feet) ahead of the advancing fill. Extending the fabric further could cause the fabric to rupture as friction develops between the fabric and the ground, which could prevent advancing the fabric towards the fill due to settlement of the ground. The geotextile shall be adequately secured so that it is not displaced during subsequent construction. No traffic or construction equipment will be permitted to operate directly on the geotextile. Any damaged geotextile shall be repaired to the satisfaction of the Engineer by patching and sewing. S-1.13 MEASUREMENT AND PAYMENT Measurement will be made of the number of square yards [square meters] of satisfactorily installed geotextile approved by the Engineer. No allowance will be made for seams. Payment will be made under Item 2105.604 (Geotextile Fabric Type V) at the Contract bid price per square yard [square meter], which shall be compensation in full for all work including, but not limited to, geotextile, seaming, placement, anchoring, and any needed repairs.
(2105) PIEZOMETER This work shall consist of installing Vibrating Wire Piezometers (VWP) within the peat/organic silt material to adequately analyze the groundwater response to the stage construction surcharge process. The work shall be accomplished according to MnDOT 2105, these Special Provisions, or as directed by the Engineer. S-1.14 MATERIAL REQUIREMENTS Vibrating Wire Piezometers shall be Geokon model number 4500 or an approved equal. The Piezometer Portable Readout Device shall be a GK-404 or an approved equal. An alternative option to the portable readout device would be to have a post-mounted battery-powered data logger capable of automatic data collection at 12-hour or shorter intervals. S-1.15 CONSTRUCTION REQUIREMENTS Each VWP shall be installed within its specific piezometer borehole at the recommended target tip elevation location listed in the table below:
Each VWP, once placed in the borehole at the recommended target tip elevation, shall be installed per the fully grouted method (Installation C-grout mixed to match soil conditions). The tip material shall be verified and recorded during installation. VWPs shall only be installed within compressible organic soils. Communication cables existing the borehole should run through conduit with strain relief (or exposed and snaked, if in sand soils), to an area outside of the surcharge footprint, away from potential construction traffic or other detrimental conditions. Piezometer cables should be secured to a post, with accessible leads, to manually read the piezometer from the portable readout device or post-mounted data collector. The cable length shall factor in
sensor installation depth, distance from installation to monitoring point, associated strain relief distance, and an extra 10 feet. To evaluate cumulative settlement and rate of settlements, reading/surveying of the piezometers shall follow this schedule at a minimum:
• Immediately prior to the placement of each stage • Immediately after completion of each stage • 1, 3, 7, 14 days after completion of each stage • Biweekly reading thereafter until settlement is judged and completed by the geotechnical engineer.
In addition, it is imperative that field baseline readings are gathered for each piezometer within 1 hour prior to installation, according to manufacturer recommendations.
The survey data from each fill increment will be evaluated by a geotechnical engineer before any additional fill is placed. The evaluation will verify that pore pressures within the foundation soils have dissipated sufficiently to avoid embankment failure and to check the amount and rate of settlement.
Surveying and recording of all of this data will be negotiated between the engineer and the contractor prior to the surcharge soil correction process. If the contractor is to complete the surveying/recording, each borehole shall have its VWP installation record prepared stating the amount of VWP(s) within the borehole, corresponding piezometer ID(s), serial number(s), dates, ground elevations, borehole depths, tremie pipe lengths, piezometer distance from the bottom of tremie pipe, tremie pipe stick up, field baseline reading, sketch of cable run, any relevant drilling installation notes, and a copy of the calibration certificate(s). If the engineer is to complete the surveying/recording, the contractor shall coordinate and cooperate as needed for obtaining said information.
S-1.16 MEASUREMENT AND PAYMENT The Engineer will measure and payout per each completed piezometer boring. All VWPs regardless of the number of required target tip elevations needed to be met per each boring are incidental. Each piezometer boring shall include the labor, drilling, placement of the VWP(s), VWP(s), communication cables, portable readout devices or post-mounted data logger, grouting of the boreholes, survey/recording of the data, removal of the equipment, etc.
(2105) SETTLEMENT PLATES
SP2016-85 This work shall consist of furnishing and installing settlement plates in accordance with the
"Settlement Plate" detail in the Plan, the provisions of MnDOT 2105, and the following: S-1.17 The Contractor shall furnish and install settlement plates at the approximate locations in the table below:
Station Offset from Centerline
(feet) Target Soil
Type Target Elevations
(feet)
146+00 0 Ground Surface 970
146+00 25 (left) Ground Surface 970
146+00 35 (right) Ground Surface 970
147+00 0 Ground Surface 970
147+00 25 (left) Ground Surface 970
147+00 35 (right) Ground Surface 970
148+00 0 Ground Surface 970
148+00 25 (left) Ground Surface 970
148+00 35 (right) Ground Surface 970
�
Station Offset from Centerline
(feet) Target Soil
Type Target Elevations
(feet) 153+00 0 Ground Surface 970
153+00 20 (left) Ground Surface 970
153+00 35 (right) Ground Surface 970
154+00 0 Ground Surface 970
154+00 20 (left) Ground Surface 970
154+00 35 (right) Ground Surface 970
155+00 0 Ground Surface 970
155+00 20 (left) Ground Surface 970
155+00 35 (right) Ground Surface 970
� The settlement plates shall be placed within 3 feet of the VWP locations, where required, so that settlement readings can be correlated to the pore water pressure measurements. One foot intervals shall be marked on the riser pipes of the settlement plates to assist in controlling lift thicknesses. S-1.18 The Contractor shall maintain the settlement plates to the satisfaction of the Engineer. The riser pipe shall be extended at least 10 feet above the grade and flagged so that they can be seen by the equipment operators. If settlement causes the riser to tilt more than 10 degrees, re-work to bend the riser back to vertical shall be incidental. Any plates damaged by the Contractor's operations shall be repaired or replaced at the Contractor's own expense. S-1.19 Bidders are advised that County forces will monitor the settlement plates during the tenure of this Contract. The Contractor shall cooperate with said forces in a manner consistent with the provisions of MnDOT 1505. S-1.20 Measurement will be made by the number of settlement plates furnished and installed as specified. Payment will be made under Item 2105.602 (Settlement Plates) at the Contract bid price per each, which shall be payment in full for all costs incidental thereto.
(2105) WICK DRAINS This work shall consist of installing wick drains within the peat/organic silt material. The work shall be accomplished according to MnDOT 2105, these Special Provisions, or as directed by the Engineer. S-1.21 MATERIAL REQUIREMENTS Wick drain material should be used per manufacturer’s specifications. The equivalent diameter of the wick drain should be 0.17 feet or greater.
S-1.22 CONSTRUCTION REQUIREMENTS Wick drains shall be installed per manufacturer’s guidelines once the geotextile fabric, monitoring instruments and the Stage 1 lift is placed. Wick drains shall be installed within the footprint of the proposed embankment and should extend to the bottom of the swamp deposit (peat/organic silts).
Installation of the wick drains shall be performed by a mandrel and placed 5 feet apart in an equilateral triangular array.
S-1.23 MEASUREMENT AND PAYMENT The Engineer will measure and payout linear feet of installed and completed wick drains. All work shall include labor, wick drain material, mandrel, flag identification, inspection, etc.
(2106) COMMON EMBANKMENT SPECIAL (CV)
This work shall consist of placing common embankment special for the surcharge soil correction process. The work shall be accomplished according to MnDOT 2106, these Special Provisions, or as directed by the Engineer. S-1.24 MATERIAL REQUIREMENTS Common Embankment Special shall conform to the requirements of Common Embankment in Table 2106-1. S-1.25 CONSTRUCTION REQUIREMENTS Common Embankment Special shall be placed on top of the Select Granular Embankment Special Material per the surcharge process. Common Embankment Special shall be placed in thicknesses according to the Table below:
������������� �������������������
����� �������������������
�������� �� ��������� � �������� � ��������� � ��
�� ����� ���� ����� � �
The contractor shall not place any more or less material than the specified amount in any area per stage, unless directed by the Geotechnical Engineer, as failure to do so may cause overstress and ultimately shear failure. Placing Common Embankment Special material shall commence from the outer edge of the proposed surcharge embankment. This will control lateral and vertical deformations that will occur as fill is placed along with providing a level surface on to which will help achieve successfully compacted lifts. The common embankment side slope shall be maintained at a 1:4 (vertical: horizontal). The layer thickness shall be controlled by depth measurements. Compaction of Common Embankment Special shall be 95 percent of its standard proctor maximum dry density. If the Common Embankment Special is placed within 3 feet of the proposed pavement subgrade, it shall be 100 percent of its standard proctor maximum dry density. See geotechnical report for expected settlement of the surcharge embankment during each stage.
The removal of material following the completion of the surcharge duration should only consist of material above the grading grade. No additional removal below the grading grade shall be completed as that may cause a rebound in soil settlement. S-1.26 MEASUREMENT AND PAYMENT The Engineer will measure embankment material quantities by volume in accordance with 1901 “Measurement of Quantities.” Confirming layer thicknesses will be checked through depth measurements rather than surveying because the fill will settle as it is placed. The engineer will measure all embankment quantities by compacted volume (CV). Removal of Common Embankment Special material to the grading grade will be included in this bid item as it is part of the staged surcharge process. The contractor can choose to recycle this material on-site and use as 2106 Common Embankment but no additional compensation will be given in doing so.
(2106) SELECT GRANULAR EMBANKMENT SPECIAL (CV) This work shall consist of placing select granular embankment special for the surcharge soil correction process. The work shall be accomplished according to MnDOT 2106, these Special Provisions, or as directed by the Engineer. S-1.27 MATERIAL REQUIREMENTS Select Granular Embankment Special shall conform to the requirements of Select Granular Embankment in Table 2106-1. S-1.28 CONSTRUCTION REQUIREMENTS Select Granular Embankment Special Material shall be placed on top of the geotextile fabric type V per the surcharge process. It shall be placed in the defined area according to the plans using 1:4’s for embankment slopes. The Select Granular Embankment Special material shall be placed in thicknesses according to the Table below:
������������� �������������������
����� �������������������
�������� � ��������� �� ��
� � �
The contractor shall not place any more or less material than the specified amount in any area per stage, unless directed by the Geotechnical Engineer, as failure to do so may cause overstress and ultimately shear failure. Placing Select Granular Embankment Special material shall commence from the toe of the proposed embankment (along the outside edges of the fabrics) and proceeding to the middle. The fill placement along the outer edges of the fabric shall extend approximately 30 to 50 feet of the width ahead of fill placement over the interior width area. This will control lateral and vertical deformations that will occur as fill is placed along with providing a level surface on to which will help achieve successfully compacted lifts. Compaction of Select Granular Embankment Special shall be 95 percent of its standard proctor maximum dry density. Layer thickness shall be controlled by depth measurements. See geotechnical report for expected settlement of the surcharge embankment during each stage.
S-1.29 MEASUREMENT AND PAYMENT The Engineer will measure embankment material quantities by volume in accordance with 1901 “Measurement of Quantities.” Confirming layer thicknesses will be checked through depth measurements rather than surveying because the fill will settle as it is placed. The engineer will measure all embankment quantities by compacted volume (CV).
(1404) MAINTENANCE OF TRAFFIC AND (2563) TRAFFIC CONTROL This section shall be amended into the current Division S (1404) Maintenance of Traffic and (2563) Traffic Control section:
S-1.30 LOCAL ACCESS AND MAINTENANCE Access to local streets and individual properties fronting or requiring access from TH 5, CSAH 10, Orchard Rd, 94th St, or Community Dr. shall be maintained on inplace, temporary, or permanent roadway, or by an alternate access. Driveways and local streets to remain open are identified in the Plans. Closure of the local roadways identified on the Plans to remain open shall not be permitted. Closure of the driveways identified on the Plans to remain open shall only be permitted if an alternate drive or access is available or constructed and the alternate access is agreed to by the property owner. If alternate access cannot be provided, paving of these driveways shall be staged to construct the new driveway before the existing driveway is removed, or the work must be staged to construct half the driveway at a time while maintaining access. Local access and maintenance of gravel roadways that are impacted per construction closures and detours included in the 2563 Traffic Control bit item will consist of 102nd St., Oak Ave, 78th St, and Paul Ave. Grading roadways may be needed to property apply the calcium chloride solution and/or correct road surfaces from additional traffic caused by construction activity. Grading/correcting/smoothing of these roadways is incidental but any additional labor to other tasks, equipment or materials needed per engineer’s orders will be made as Extra Work.
AA/EOE
Braun Intertec Corporation p11001 Hampshire Avenue S Minneapolis, MN 55438
March 27, 2017 Project B1608361 Dan Lonnes, PE Bolton & Menk, Inc. 2638 Shadow Lane, Suite 200 Chaska, MN 55318 Re: Geotechnical Evaluation CSAH 10 West Ring Road Segment II CSAH 10 between North of the Roundabout at Community Drive to the Project Terminus Waconia, Minnesota Dear Mr. Lonnes: We are pleased to present this Geotechnical Evaluation Report for Segment II of the CSAH 10 West Ring Road between north of the roundabout at Community Drive to the project terminus. A general summary of our recommendations in light of the geotechnical issues influencing design and construction is presented below. More detailed information and recommendations can be found in the body of the report. Key design and construction components of Segment II covered in this report include recommendations for embankment support including a stage constructed surcharge through highly compressible soils, foundation recommendations for a pedestrian underpass and a pedestrian bridge, subgrade recommendations, and pavement R-value recommendations. Summary of Recommendations Most of the borings outside the swamp crossing encountered fill and/or topsoil above clay till. Very deep soft to very soft swamp deposits consisting of organic silt, organic clay and peat overlying clay till were encountered in the swamp borings and cone penetration test (CPT) soundings within the undeveloped agricultural land. We do not recommend relying upon the existing fill, organic deposits and topsoil for direct support of the pavement and embankment. Re-use of the clayey soils encountered in the borings as fill will require moisture conditioning (drying) of the soils. Topsoil and organic soils should not be re-used as structural fill. For support of the roadway embankment and pavements in the swamp crossings, we recommend installing prefabricated vertical drains (PVDs) or “wick drains” within the recommended surcharge to reduce the long-term settlement of the soft organic silt and peat prior to embankment construction. We estimate between 6 to 7 feet of settlement could occur through the staged construction surcharge process that could take 6 to 9 months to complete with long term settlements on the order of a 1/2 foot. Pavement can be supported on the surcharge fill once consolidation is judged to have leveled off from the instrumentation data obtained.
Table of Contents Description Page A. Introduction ...................................................................................................................................... 1
A.1. Background .......................................................................................................................... 1 A.2. Project Description and Information ................................................................................... 1 A.3. Purpose ................................................................................................................................ 2 A.4. Reference Documents ......................................................................................................... 2 A.5. Scope of Services ................................................................................................................. 3
B. Results .............................................................................................................................................. 4 B.1. Exploration Logs .................................................................................................................. 4
B.1.a. Log of Boring and Sounding Sheets ........................................................................ 4 B.1.b. Geologic Origins ..................................................................................................... 5
B.3. Laboratory Test Results ....................................................................................................... 7 C. Discussion ......................................................................................................................................... 8
C.2. Construction Considerations ............................................................................................. 10 D. Recommendations ......................................................................................................................... 11
D.1. PVDs and Surcharge Analyses ........................................................................................... 11 D.1.a. Mitigation Alternatives for Embankment Construction ....................................... 11 D.1.b. Material Properties .............................................................................................. 12
E. Utilities ........................................................................................................................................... 32 F. Construction Equipment Support ................................................................................................... 33 G. Procedures...................................................................................................................................... 33
G.1. Penetration Test Borings ................................................................................................... 33 G.2. Cone Penetration Test Soundings ..................................................................................... 33 G.3. Power Auger borings ......................................................................................................... 34 G.4. Material Classification and Testing ................................................................................... 34
G.5. Groundwater Measurements ............................................................................................ 34 H. Qualifications .................................................................................................................................. 35
H.1. Variations in Subsurface Conditions .................................................................................. 35 H.1.a. Material Strata ..................................................................................................... 35 H.1.b. Groundwater Levels ............................................................................................. 35
H.2. Continuity of Professional Responsibility .......................................................................... 35 H.2.a. Plan Review .......................................................................................................... 35 H.2.b. Construction Observations and Testing ............................................................... 36
H.3. Use of Report..................................................................................................................... 36 H.4. Standard of Care ................................................................................................................ 36
Table of Contents (continued) Description Page
Appendix A Soil Boring Location Sketch Log of Boring Sheets B-14 through B-19 Log of Boring Sheets PAB-1 through PAB-4 MnDOT Descriptive Terminology of Soil Logs of Boring Sheets C-1, C-2 and C-5 Log of Boring Sheets R-3 through R-22 Braun Intertec Descriptive Terminology of Soils Log of CPT Soundings R-1, R-2, and S-1 through S-12 Braun Intertec CPT Descriptive Terminology Oedometer Test Results Appendix B Analytical Graphics: Construction Induced Pore Water Pressure Parameters Analytical Graphics: Slope/W Graphics for Surcharge Embankment Stability Analyses Appendix C Analytical Graphic: Limit State Graph for PMBW Foundation Analytical Graphics: PMBW Global Stability (Short and Long Term)
A. Introduction
A.1. Background We submitted a Geotechnical Evaluation Letter for Preliminary Design for Segment II improvements under a separate cover (Braun Intertec Project number B1601000, dated July 28, 2016) where we discussed the subsurface conditions encountered in a limited number of Phase I borings and laboratory testing performed. The alignment within the agricultural land was yet to be finalized during Phase I letter submission. We also submitted Geotechnical Evaluation Reports for Segment I of County State Aid Highway (CSAH 10) between Highway 5 and Community Drive, and Community Drive and 94th Street under separate cover (Braun Intertec Project numbers B1601000, dated July 28, 2016, and B1601003, dated July 28, 2016, respectively).
A.2. Project Description and Information This Geotechnical Evaluation Report addresses the final design of Segment II of the proposed CSAH 10 West Ring Road near Waconia, Minnesota. Segment II refers to the proposed alignment north of the roundabout at Community Drive to the project terminus, which is depicted on the attached project location sketch. The alignment of Segment II is also proposed to extend through an undeveloped agricultural land between Community Drive roundabout and Waconia Parkway. Historically, the site was undeveloped agricultural land. Current grades at the site range in elevations from 980 to 990 feet within the agricultural land above Mean Sea Level (MSL). The grades adjacent to the proposed underpass structure near Waconia Parkway range in elevations from 1000 to 1010 feet MSL. Generally, the site slopes downward, from northwest to southeast. The pedestrian underpass will be located on the south side of the proposed Waconia Parkway roundabout and will carry pedestrian traffic from the south trail along CSAH 10 beneath Waconia Parkway and connect to the northeast trail along Waconia Parkway. Based on the information provided, the pedestrian underpass will consist of a precast Reinforced Concrete Box Culvert (RCBC) segmental sections with an inside height and width of 12'-0" by 10'-0" with a 20-foot long “U” shape end section on the west end. Two Prefabricated Modular Block Walls (PMBW), each approximately 76 feet long and 11 feet high (exposed height), will retain the cut slope on the east end of the culvert. The total length of the proposed underpass will be approximately 126 feet.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 2
The prefabricated pedestrian truss bridge will be located on the east side of the pedestrian underpass to carry the northeast trail over the south trail and be supported by two 4-foot wide stub abutments.
A.3. Purpose The purpose of this geotechnical evaluation was to further characterize subsurface geologic conditions and provide geotechnical recommendations for Segment II roadways and trail support, pedestrian underpass, pedestrian bridge, and PMBWs.
A.4. Reference Documents To facilitate our evaluation, we were provided with or reviewed the following information or documents:
� Geotechnical Evaluation Letter for Preliminary Design, CSAH 10 West Ring Road – Segment II by Braun Intertec (Braun Intertec Project number B1601000), dated July 28, 2016.
� 95% Plan submittal by Bolton & Menk, dated November 30, 2016.
� Final Plan submittal by Bolton & Menk, dated March 3, 2017.
� Modular Block Wall Plan and Section by Bolton & Menk, February 3, 2017.
� Box Culvert Plan and Section by Bolton & Menk, February 3, 2017.
� Piezometer readings near underpass structure collected from Boring C-5.
� Aerial images with boring locations from Google Earth.
� Surficial Geology of the Twin Cities Metropolitan Area Map by the University of Minnesota Geology Survey (dated 2007).
� Soil Mechanics in Engineering Practice by Tergazhi, Peak and Mesrie, Third Edition, 1996. � Embankments on Organic Soils by Hartlen and Wolski, Volume 80, First Edition, 1996 � A New Design Procedure for Stability of Soft Clay, ASCE Volume 100, GT7, PP 736-786.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 3
A.5. Scope of Services Our scope of services for this project was originally submitted as a Proposal to Mr. Dan Lonnes of Bolton & Menk, Inc. We received authorization to proceed from Mr. Kyle Johnson on February 9, 2016. The scope was subsequently revised and approved via email, dated September 27, 2016, and change order, dated January 31, 2017, to include additional soil borings and CPT soundings to gather additional information along the new alignment and swamp crossings. Tasks performed in accordance with our authorized scope of services included:
� Performing a reconnaissance of the site to evaluate equipment access to exploration locations.
� Staking and clearing the exploration location of underground utilities. Exploration locations and surface elevations at the exploration locations were determined using GPS (Global Positioning System) technology that utilizes the Minnesota Department of Transportation’s permanent GPS Virtual Reference Network (VRN).
� Drilling 21 penetration test borings, numbered R-3 through R-22 (5 penetration test borings, numbered B-15 through B-19, were drilled during Phase I by our subcontractor, STS Enterprises, LLC [STS]), to depths ranging from 11 to 61 feet below grade. The deeper borings were drilled near the swamp crossings.
� Performing 14 CPT soundings, numbered R-1, R-2, and S-01 through S-12, to depths ranging from 15 to 56 feet below grade to delineate and characterize the swamp crossing.
� Performing two soil borings, numbered C-1 and C-2, near the underpass structure to nominal depths of 51 feet each.
� Installing one standpipe piezometer near the proposed underpass structure to verify the groundwater level in the area.
� Performing four Power Auger Borings (PAB), numbered PAB-1 through PAB-4, along Trunk Highway (TH) 5 to facilitate pavement design.
� Performing laboratory moisture content, density and organic content and oedometer (one-dimensional consolidation) and time-rate consolidation tests on selected penetration test and Shelby tube samples.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 4
� Performing engineering analyses for embankment support at the swamp crossings.
� Perform engineering analyses for bearing capacity and settlement for the proposed pedestrian underpass, bridge and PMBWs.
� Preparing this report containing a CAD sketch, exploration logs, a summary of the geologic materials encountered, results of laboratory tests, and recommendations for design of roadways, pedestrian underpass and bridge structures, PMBWs and pavements.
Our scope of services was performed under our Master Subconsultant Agreement for Professional Services dated December 10, 2013 or January 1, 2017, which also included a Phase I Environmental Assessment. These deliverables were submitted under separate cover.
B. Results
B.1. Exploration Logs
B.1.a. Log of Boring and Sounding Sheets Log of Boring sheets for Standard Penetration Test (SPT) borings are included in the Appendix. The logs identify and describe the geologic materials that were penetrated, and present the results of penetration resistance (SPT blow counts) and laboratory tests performed on penetration test and thin wall samples retrieved from them, and groundwater measurements. Strata boundaries were inferred from changes in the penetration test samples and the auger cuttings. Because sampling was not performed continuously, the strata boundary depths are only approximate. The boundary depths likely vary away from the boring locations, and the boundaries themselves may also occur as gradual rather than abrupt transitions. The Appendix also includes CPT Sounding Logs. The CPT sounding logs report the tip resistance (Qt), sleeve friction (Fs) and pore pressure (U2) measured by the cone during advancement, as well as, the soil behavior type (SBT) inferred from established relationships between tip resistance, sleeve friction and pore pressure. The SBT does not indicate a soil classification based on grain size distribution. Refer to the attached CPT Descriptive Terminology in the Appendix for more information. The CPT logs also report the friction ratio, which calculated by dividing the sleeve friction by the tip resistance. We inferred strata boundaries, like SBT, from changes in tip resistance, sleeve friction and pore pressure. While cone measurements are relatively continuous with depth, the boundaries are still only approximate, likely vary away from the sounding locations and may also occur as gradual rather than abrupt transitions.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 5
B.1.b. Geologic Origins We based the geologic origins used in this report on the soil types, in-situ and laboratory testing, and available common knowledge of the geological history of the site. Because of the complex depositional history, geologic origins can be difficult to ascertain. We did not perform a detailed investigation of the geologic history for the site.
B.2. Geologic Profile
B.2.a. Geologic Materials The general geologic profile at the site consists (proceeding down from the ground surface) of fill/topsoil, peat or organic soil overlying glacial till. Please refer to the soil boring and CPT logs attached for a more in-depth summary of the observed soils. B.2.b. Roadway Borings and CPTs Borings R-5 and R-16 encountered bituminous concrete over 4 to 6 inches of aggregate base. These borings were drilled along the existing Waconia Parkway. Borings R-3, R-4, R-6 through R-15, and R-16 through R-18 encountered topsoil to depth of up to 2 1/2 feet below the ground surface. Borings R-3 through R-5, R-7, R-8, R-12 through R-14, and R-16 through R-18 encountered fills consisting of sandy lean clay and lean clay to a maximum depth of 12 feet below ground surface. Penetration tests in the fill ranged from 3 to 14 blows per foot (BPF) indicating that the density of the fill soils is variable. Borings R-17, R-19, R-20, R-22, B-14, B-15, B-16, and CPTs S-01 through S-12 encountered swamp deposits consisting of peat, organic silt and organic clay. The thickness of the swamp deposits ranged from a couple of feet up to 45 feet. Penetration tests performed in the SPT borings ranged primarily from Weight of Hammer (WH) to 4 BPF indicating very soft to soft consistencies. The CPT sounding tip resistances and friction ratios ranged from less than 5 tsf and 2 to 6 percent, respectively. Glacial till was encountered at the surface or beneath the fill, topsoil, or swamp deposits in all borings and CPTs. Glacial till generally consisted of lean clay, sandy lean clay, silt and silty sand, and extended to the termination of all borings with the exception of Boring B-17 where glacial outwash sands were identified beneath the till. Penetration tests in the glacial till (cohesive) ranged from 2 to 18 BPF,
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 6
indicating very soft to very stiff consistencies and the penetration test in the glacial outwash (non-cohesive) was 11, indicating a medium dense relative density. Frost was observed near the surface in many of the borings completed in the winter months. Please refer to the attached boring logs for specific frost depths. SPT values were inflated in the portion of soil layers where frost was observed. B.2.c. Pedestrian Bridge and Underpass Borings Topsoil was encountered at the surface in Borings C-1 and C-5, consisting of sandy lean clay or clayey sand to a depth of about 2 feet below the ground surface in Boring C-1 and 1 foot below the ground surface in Boring C-5. Boring C-2 encountered fill to a depth of about 6 feet below the existing ground surface. The fill encountered by Boring C-2 primarily consisted of sandy lean clay and was in a moist to wet condition. Penetration resistance tests in the fill soils varied from 7 to 14 blows per foot (BPF) indicating variable compaction levels. Beneath the fill and topsoil, the borings encountered glacially deposited lean clay, sandy lean clay and silt with a glacial outwash layer encountered in Boring C-1 between depths of 45 and 48 feet below existing grade. Penetration resistance values recorded in the glacial tills (cohesive) varied from 5 to 21 BPF, indicating rather soft to very stiff consistencies. The Penetration resistance value recorded in the glacial outwash sands was 35 BPF, indicating a dense relative density.
B.2.d. Power Auger Borings Bituminous pavement underlain by 12 inches of aggregate base were encountered in all the roadway borings, labeled as PAB-1 through PAB-4. Beneath the pavement structure, the borings encountered moist sandy lean clay to their termination depth.
B.2.e. Groundwater Groundwater was observed in Borings C-1, C-2, R-3, R-4, R-7, R-10, R-16, R-19, R-20, B-15, B-17 and B-19 during drilling. Depths to groundwater varied from approximately 8 1/2 to 46 1/2 feet below existing grade. Given the cohesive nature of the geologic materials encountered, however, it is likely that insufficient time was available for groundwater to seep into the boreholes and rise to its hydrostatic level. Piezometers or monitoring wells would be required to confirm if groundwater was present at a specific elevation within the depths explored. One standpipe piezometer was installed at Boring C-5 near the pedestrian bridge and underpass to monitor groundwater levels in this area. The results from the water levels collected are included in the table below.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 7
Table 1. Piezometer Readings in Boring C-5
Piezometer Readings
Date Ground Elevation
(Feet MSL) Groundwater Elevation
(Feet MSL)
12/15/2016 1015.7 1007.0
12/30/2016 1015.7 1007.3
1/5/2017 1015.7 1007.0
1/16/2017 1015.7 1005.8
2/2/2016 1015.7 1005.3
Based on the observations, the groundwater is located approximately 9 to 11 feet below the ground surface between elevation 1005 and 1007 feet MSL. However, based on the soil coloring observed in the borings, publically available well information and topography, the groundwater elevation obtained from the piezometer is likely perched water within the silt and sand seams trapped between confining, more cohesive soils. Seasonal and annual fluctuations of groundwater should also be anticipated.
B.3. Laboratory Test Results Selected soil samples were submitted to our laboratory for testing. The laboratory tests were completed in general accordance with current ASTM procedures and generally consisted of moisture contents, organic contents, densities and unconfined compression strength tests. The index test results, moisture contents, organic contents, and densities can be found on the Log of Boring sheets opposite the soil sample tested in the Appendix. The undrained shear strength of the clay till sample taken from Boring R-4 was 1,630 psf. We also completed seven oedometer tests: one on a sample of lean clay fill taken from Boring R-7, one on the sample of clay till taken from Boring R-19, and five on samples of organic soils taken from Borings R-20 and R-22, on thin wall samples. We tested the fill sample in our laboratory and the organic and clay till samples at a nearby geotechnical laboratory (Soil Engineering Testing). Each test consisted of applying a series of load increments (load increment ratio of 2) to the sample, measuring the rate at which the samples consolidated under each load, and then observing the expansion that occurred at incremental unloading. The test results are included in the Appendix. Results of the oedometer tests are summarized in the table below.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 8
Table 2. Summary of Oedometer (1D and Time Rate) Test Results
The organic contents of the oedometer samples can be found in the boring logs opposite the sample tested. Oedometer test results indicated the peat, organic silts and organic clays are highly compressible and relatively impermeable. The SPT blow counts and the oedometer test results indicated the underlying clay tills are moderately to heavily over-consolidated, i.e., at some point of time in the geological past, it has been consolidated under heavier loads in excess of the anticipated embankment loading. We do not expect significant consolidation of the underlying clay till under the proposed embankment and surcharge loading.
C. Discussion
C.1. Design Details
C.1.a. Pavements and Traffic Loads Light-duty pavement areas will have a bituminous section and our scope of services did not include providing a pavement section recommendation. Please refer to Section D.5 for R-value recommendations.
C.1.b. Anticipated Grade Changes Existing ground surface elevations are within approximately 2 to 23 feet of the proposed roadway. Cuts on the order of 9 feet or less are therefore anticipated along the alignment. The maximum cut on the order of 23 feet is anticipated near the underpass structure at Waconia Parkway. Fills on the order of 2 to
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 9
12 feet are anticipated for the roadway. The portion of Segment II within the agricultural land will undergo a raise in grade of approximately 5 to 12 feet. Additionally, 5 to 10 feet of fill is anticipated along areas of Waconia Parkway to achieve final design grades.
C.1.c. Roadway Embankment Support Based on the site investigation data obtained, the alignment within the agricultural land will be supported on two very deep and highly compressible swamp deposits encountered in valleys with steeply sloped sides that can reach depths in excess of 40 feet. These areas are expected to settle over time under the proposed embankment loads. We understand it is desired to install prefabricated vertical drains (PVDs) or “wick drains” into the swamp crossings with a staged constructed surcharge to speed up consolidation of the compressible soils to meet the planned construction schedule. Construction of pavement and other utility structures within the swamp crossings should be started after the consolidation of the peat and organic soils are judged to have leveled off to an acceptable tolerance and excess surcharge fills are removed. We anticipate further settlement of the embankment due to secondary consolidation of the organic silts, clays and peat over time. Estimates of the settlement magnitudes and time for consolidation are unpredictable by the thicknesses of the organic soils encountered, highly variable consolidation parameters, uncertainty with regard to the degree of consolidation, and the likelihood of disturbance to foundation soils. The estimated settlements provided in this report should be considered approximate and determination of the end of the surcharge will be dependent on the results of the instrumentation monitoring obtained. In areas outside the swamp crossing, it is our opinion the soils present at the anticipated structure subgrade elevations generally appear suitable for support of pavements after standard pavement removals and/or vegetation/topsoil stripping. Some shallow soil corrections may be required prior to roadway construction to remove and replace poorly compacted fills, which in their current condition, are judged unsuitable for embankment support. A geotechnical engineer or their representative should evaluate the exposed subgrade soils prior to pavement placement to assess the extent of corrections required. Due to the frost-susceptible nature of the silt- and clay-rich soils present at anticipated pavement subgrade elevations, consideration should also be given to incorporating a granular subbase into the pavement sections. A granular subbase enhances subgrade drainage, reduces the potential for pavement subgrades to become saturated and heave upon freezing, and reduces the effects of subgrade strength loss upon thawing.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 10
C.1.d. Pedestrian Bridge and Underpass The native soils present at the foundation subgrade appear suitable for support of the underpass structure and the walls, which is anticipated to consist of a 24-inch thick layer of Granular Bedding (MnDOT Specification 3149.2F) overlying native glacial till. Minor soil correction may be required if soft or unsuitable soils are encountered during foundation excavation. The stub abutments of the pedestrian bridge will be supported on the engineered fill (Select Granular Material) approximately 11 feet behind the PMBW retaining walls. The wall designer should verify the structural stability of the wall due to abutment loading.
C.1.e. Utilities Utilities placed within the roadway through the swamp crossings should be re-located outside of the embankment core and installed after the surcharge within the swamp crossings are removed. Additional maintenance may be necessary with buried utilities due to secondary compression of the organic silts, clays and peat over time. Soils encountered elsewhere along the project alignment at typical invert elevations are judged suitable for utility support with typical bedding placement.
C.2. Construction Considerations From a construction perspective, the project team should also be aware that:
� Excavations to remove unsuitable soils may encounter groundwater. Temporary dewatering may be required to facilitate an evaluation of the soils exposed in the excavation sides and bottoms, and the placement and compaction of backfill.
� Debris and organic soils will have to be removed from the existing fill before it can be reused; this will not only limit the reusable volume, but will also increase the time required to handle the existing fill. The fill is also wet and will need to be dried to facilitate compaction.
� The clays present below the existing fill will also need to be dried to facilitate compaction. Given the anticipated depths of the roadway excavations, the thickness of clay placed in an excavation will also have to be restricted to limit the amount of post-construction settlement that occurs from the excavation backfill compressing under its own weight.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 11
� Because there are no such resources on the site, sands or gravels will have to be imported to backfill the balance of excavations that can only be partially backfilled with clay, and facilitate drainage below pavements.
� Haul roads and staging areas will be particularly sensitive to disturbance and strength loss. Subexcavation and re-compaction or replacement of subgrade soils can be limited if these traffic areas are protected with crushed rock.
� Surface features including pavements and sidewalks that are to be placed within swamp crossing should be designed and constructed to account for the long-term secondary consolidation settlement.
D. Recommendations In accordance with our findings and discussions with Bolton & Menk and Carver County (County), below are our recommendations for surcharging with PVDs, structure foundation recommendations, and subgrade preparations and pavement R-value.
D.1. PVDs and Surcharge Analyses
D.1.a. Mitigation Alternatives for Embankment Construction The embankment within the swamp crossings will carry two 20-foot wide pavements, a median of varying width, and a 10-foot wide pedestrian trail. Grades will be raised approximately 6 to 8 feet within the swamp areas. Very deep swamp deposits consisting of very soft to soft organic silt and peat precluded muck excavation and shallow groundwater precluded use of lightweight fill (such as shredded tires, geofoam, etc.). Based on the discussion with the project team, we reviewed the following settlement mitigation alternatives for roadway embankment support:
� Surcharge with wick drains. � Surcharge without wick drains.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 12
For each case, we estimated the time required to complete the predicted long-term settlement and short-term factor of safety of the interim surcharge embankment at each construction stage to verify surcharge embankment stability against failure. Based on our estimates, the time required for completing the predicted total long-term settlements (settlement of embankment after 20 years) of 85 and 80 inches for “Surcharge with Wick Drains” option was 6 to 9 months and for “Surcharge without Wick Drains” option was 24 to 36 months. Because the time required for “Surcharge without Wick Drains” option would likely take longer than available, it was determined most feasible to proceed with the “Surcharge with Wick Drains” option for this project. Consequently, we discussed design and analyses of the wick drains and surcharge and presented the results in the following sections. Surcharge is a commonly used ground improvement technique to reduce the compressibility of soft soils through consolidation, i.e., dissipation of excess pore water pressure induced from additional loading, by applying loads on the ground surface for a certain period of time and then removed once consolidation is completed. When the surcharge is removed, the soil rebounds. During the application of a surcharge, the soft soil settles over time and the compressibility and strength properties improve. Typically, a surcharge on soft soil is constructed in stages to reduce the risk of embankment failure by sliding. The thicknesses and waiting periods between stages are generally controlled by the undrained shear strength of the soft soil. Wick drains encased in a filter fabric are inserted vertically within the soft soils to provide a preferential flow path and are installed in addition to the surcharge to further accelerate the consolidation process. Wick drains initiate horizontal flow of water into the drain, which are then expelled at the surface.
D.1.b. Material Properties
D.1.b.1. Consolidation Parameters A summary of the primary consolidation parameters measured or estimated, and ultimately applied to the soil strata in Settle 3D models, is presented in the tables below. We estimated the consolidation parameters based on the oedometer test results and our experience with similar soils in the area. The overconsolidation ratios were interpreted from CPT sounding data.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 13
Table 3. Assigned Consolidation Properties at Station 147+00
Soils
Initial Void Ratio,
e0
Compression Index,
Cc
Swelling Index,
Cr
Overconsolidation Ratio,
Pc Permeability2, Kv
(ft/day)
Organic Silt (0’-5’)1 2.5 1 0.15 2.5 0.005
Organic Silt (5’-12’)1 3.25 1.3 0.3 1.5 0.005
Organic Silt (12’-21’)1 3.35 1.5 0.28 1 0.004
Organic Silt (21’-27’)1 3.2 1.15 0.2 1 0.003
Organic Silt (27’-35’)1 2.5 1 0.15 1 0.003
Organic Silt (35’-50’)1 3.1 1.25 0.28 1 0.005
Soft Till 0.8 0.15 0.02 4 0.1
Hard Till 0.6 0.15 0.02 8 0.1
1. Organic silts were subdivided based on natural moisture contents and organic contents to better represent in-situ soil conditions. In general, soils with higher organic contents and higher OCR have higher permeability.
2. Permeability of soils are estimated based on soil types encountered in the borings.
Table 4. Assigned Consolidation Properties at Station 154+00
Soils Initial Void
Ratio, e0 Compression
Index, Cc Swelling Index, Cr
Overconsolidation Ratio, OCR
Permeability1, Kv (ft/day)
Peat 5.5 1.5 0.4 2 0.03
Organic Silt 3.25 1.3 0.3 1 0.005
Soft Till 0.8 0.15 0.02 4 0.1
Hard Till 0.6 0.15 0.02 8 0.1
1. Permeability of soils are estimated based on soil types encountered in the borings.
The lab tested coefficient of consolidation (Cv) parameters, which is related to permeability of soils through constrained modulus (M), appears to be lower for the organic soils. One conceivable cause could be disturbance during sample collection, subsequent handing, transportation and extrusion of samples, which possibly altered the in-situ state of the soft organic soils. We used estimated permeability of the organic silt and peat presented in the table based on our test database and generally accepted published correlations. We used soil permeability in estimation of consolidation settlement and wick drain design in Settle 3D software. For secondary consolidation estimation, we used Mesrie’s secondary consolidation ratios (Cα/Cc) of 0.05 and 0.1 for organic silt and peat (Terzaghi, Peak and Mesrie, 1996).
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 14
D.1.b.2. Shear Strength Parameters We estimated the effective stress parameters for the organic silt and peat based on our experience with similar deposits in the area. We used effective stress parameters of glacial till for both short- and long-term stability analyses as glacial till appeared to be moderately to highly over-consolidated and were expected to dilate during shearing (undrained strengths will not control the stability). We modeled undrained strength of the organic soils using the Stress History and Normalized Soil Engineering Properties (SHANSEP) approach developed by Ladd and Foot (1974). This method evaluates the in-situ strength characteristics of the organic soils under different consolidation conditions based on its stress history. Undrained shear strength ratios (Su/σ’v) of 0.28 and 0.3 for organic silt and peat were adopted based on CPT data interpretation and generally accepted published correlations. These values were representative of the average undrained shear strength corresponding to simple shear failure mode within normally consolidated organic soils. We also estimated the minimum undrained shear strengths of 150 and 200 psf for peat and organic silts within the upper desiccated zone (upper 10 to 15 feet) from the CPT sounding data. Of note, the undrained strength ratio of organic soils are generally higher than the mineral soil’s undrained strength ratio, which typically ranged from 0.2 to 0.25 depending on soil plasticity. We estimated construction induced pore pressure parameters (incremental B-bar for staged construction) at each loading stage from Settle 3D generated excess pore water pressure outputs. The incremental B-bar parameters were estimated as the ratio of the change in total excess pore water pressure induced in the organic silt and peat during load application to the change in total vertical stress. The B-bar values were used in interim embankment stability analyses in Slope/W to calculate pore water pressure response from fill placement. The pore water pressure were subsequently used to estimate vertical effective stress. The vertical effective stresses were used by Slope/W to estimate undrained strength from undrained shear stress ratio (Su/σ’v) inputs. Of note, B-bar values for normally consolidated to lightly overconsolidated clays typically range from 0.75 to 1 and moderately to highly overconsolidated clays range from 0.5 to 0.75 immediately after loading depending on soil plasticity, length of drainage path, loading type (instantaneous vs ramp loading) and hydraulic boundary conditions. A summary of the shear strengths measured or estimated, and ultimately applied to the soil strata represented in our cross sections evaluated is presented in the tables below.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 15
Table 5. Assigned Material Strength Properties at Station 147+00
Material
Unit Weight
(pcf)
Effective Stress Parameters Total Stress Parameters
1. Su/σ’v = Normalised undrained shear strength ratio. 2. P1 represents long-term water table. We assumed long-term water table at 3 feet below the existing grade. 3. P2 represents temporary water level within the surcharge fill after fill placement estimated using Coupled Sigma/W analyses. 4. B-bar values at each loading stage are included in the appendix. Table 6. Assigned Material Strength Properties at Station 154+00
1. Su/σ’v = Normalised undrained shear strength ratio. 2. P1 represents long-term water table. We assumed long-term water table at 3 feet below the existing grade. 3. P2 represents temporary water level within the surcharge fill after fill placement estimated using Coupled Sigma/W analyses. 4. B-bar values at each loading stage are included in the appendix.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 16
D.1.c. Predicted Settlement The predicted primary and secondary settlements estimated using Settle 3D software and the predicted total fill thicknesses to achieve design grade (without a surcharge) after 20 years are presented in the table below. Table 7. Predicted Long-Term Settlement
Station 147+00 Station 154+00
End of Year 20 End of Year 20
Primary Consolidation (inches) 76 70
Secondary Consolidation (inches) 9 10
Total Settlement (inches) 85 80
Design Embankment Height (feet) 8 7
Total Fill Thickness (feet) 15 13 1/2
These settlement results and the associated fill thicknesses at the most critical sections were used in the wick drain and surcharge design approach, further discussed in the following sections.
D.1.d. Surcharge with Wick Drains Design Approach We used Settle 3D software to estimate the spacing of wick drains and surcharge staging required to complete the estimated settlement of 80 to 85 inches in six to nine months. Initially, we estimated the total fill thickness required to achieve the final embankment fill thickness considering total settlement (elastic, primary and secondary consolidation) of the organic clay and peat over 20 year’s period (long-term). We then designed the total surcharge thicknesses to achieve the estimated total long-term settlement within two years. We calculated the time-rate of settlement for the proposed embankments with the use of wick drains based on the following assumptions and parameters:
� The installation of the wick drain would be performed by a mandrel and would be installed to the bottom of the swamp deposit layers.
� Wick drains would be placed at 5 feet apart in an equilateral triangular array.
� The equivalent diameter of the wick drain would be 0.17 foot or greater.
� The ratio of soil permeability in the horizontal direction for the undisturbed and disturbed zones would be about 5.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 17
� The ratio of the disturbed soil diameter to the effective diameter of the wick drain would be about 3 (this value depends on the dimension of the mandrel used and will vary during actual construction).
� The ratio of the horizontal to vertical permeability within the undisturbed zone would be 5. We estimated total settlements at the end of each intermediate stage and final settlements prior to removal of surcharge. The predicted settlement values by stage are presented in the table below. Table 8. Predicted Short-Term Settlements with Wick Drains
Stage Station 147+00
(inches) Station 154+00
(inches)
Stage 1 5 13
Stage 2 34 40
Stage 3 55 55
Stage 4 67 67
Stage 5 78 76
Removal Stage 85 80
Long-term creep of the soils will still occur overtime following final roadway construction. We predict about a 1/2-foot of settlement could occur over a duration of 20 years. The aim of the surcharge design was to calculate the thickness of each stage and the wait time between the stages without adversely affecting the stability of the interim surcharge embankment. We selected two sections for each area of interest at Stations 147+00 and 154+00, which represent the deepest and widest areas where swamp deposits were encountered. In addition to being highly compressible, peat and organic silts have low strengths. Experience has shown that, if more than 5 feet of fill is placed initially, a shear failure is likely. After the initial lift has been placed, it is necessary to wait for pore water pressures to dissipate and for the organic soils to gain strength. An additional lift of fill can then be placed, followed by a consolidation and strengthening period. Thus, it is necessary to raise the embankment in stages to avoid shear failure. The surcharge staging considering wick drains are presented in the following table.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 18
Table 9. Surcharge Staging with Wick Drains
Stage No.
Station 147+00 Station 154+00
Thickness1 (ft)
Time (days)1
Thickness1 (ft)
Time1 (days)
Stage 1 4 0 4 0
Stage 2 4 30 3 30
Stage 3 3 60 3 60
Stage 4 3 90 3 90
Stage 5 3 150 2 150
Removal 1-2 180 1-2 180
1. Time starts at the beginning of Stage 1. The time and fill thicknesses presented in the table are estimates based on the interpretation of the geology from boring data and the laboratory test results. Actual durations required for the staging will be dependent on the results from the instrumentation equipment.
D.1.d.1. Embankment Stability Analyses and Results We evaluated stability of the surcharge embankments using computer program Slope/W, Version 8.16.1.13452, by Geo-Slope International using Spencer method by optimizing critical slip surfaces. Based on the analyses, we recommended 4H:1V or flatter side slopes. The results of the stability analyses for each stage are presented in the following table. Graphs illustrating each stability analyses are included in the Appendix. Table 10. Stability Analyses Results for Surcharge with Wick Drains
Analysis Case Time
(days)
Factory of Safety
Station 147+00 Station 154+00
Stage 1 0 2.1 1.6
Stage 2 30 1.6 1.5
Stage 3 60 1.3 1.4
Stage 4 90 1.3 1.3
Stage 5 150 1.2 1.2
Long-Term 180 1.8 1.8
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 19
Generally, a factor of safety of 1.2 is desired during construction, unless additional soils borings or lab testing is performed. If the factor of safety during construction is found to be less than 1.2 based on monitoring data for any stage, the staging should be modified to maintain a factor of safety of 1.2 or greater. This could be achieved by reducing fill thickness or delaying the stages to allow the pore water pressure dissipation to occur and increase the factor of safety. Each layer should be placed across the entire swamp crossing prior to placing the next layer. The long-term stability analyses indicated that the factor of safety against global failure exceeded the target factor of safety of 1.3.
D.2. PVD Installation and Surcharge
D.2.a. Anticipated Limits of Wick Drain Installation and Surcharge Based on the project plan and cross-section provided to us and the interpretation of the SPT boring and CPT data, the anticipated limits of surcharging and wick drain installation is as follows:
� North Area: � Surcharge Limits: Station 150+50 to 158+00 � Wick Drain Limits: Station 151+50 to 157+50
� South Area:
� Surcharge Limits: Station 143+00 to 149+75 � Wick Drain Limits: Station 144+25 to 149+25
Consideration should be given to extending the surcharge through the transition zone between areas identified. Extending the surcharge will help limit the differential movement that may occur between surcharge and non-surcharge zones.
D.2.b. Preparation of Subgrade We recommend placing Type V geotextile conforming to MnDOT Specifications 3733.2B on the existing subgrade. The geotextile will act as a separator between the fill and the underlying soil and distribute the fill load evenly on the underlying soils. Individual strips of fabric should first be placed perpendicular to the direction of the alignments and stich together to form a continuous sheet. Seam strength should conform to MnDOT Specification 3733.2B. Overlapping of edges of the fabric is not preferred as separation of the fabric could occur during placement of the fill and during the consolidation process. The mat should be extended the length of the surcharge alignment plus an additional 15 feet beyond either end.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 20
We recommend extending the fabric strips approximately 5 feet beyond the toes of the embankment slopes. Extending the fabric 5 feet beyond the embankment toe will help the fabric contain the embankments as they settle. We recommend extending the fabric only several strip widths (no more than 50 feet) ahead of the advancing fill. Extending the fabric further could cause the fabric to rupture as friction develops between the fabric and the ground, which could prevent advancing the fabric towards the fill due to settlement of the ground.
D.2.c. Prefabricated Vertical Drain Installation We recommend installing the wick drains once the geotextile, monitoring instruments and the first 4-foot lift is completed. Wick drains should be installed as per manufacturer’s guidelines. Wick drains should be installed within the footprint of the proposed embankment and should extend to the bottom of the swamp deposit.
D.2.d. Placing Fills To control lateral and vertical deformations that will occur as fill is placed, and provide a level surface on which to compact successive lifts, we recommend fill placement commence from the toe of the proposed embankments (along the outside edges of the fabrics). We recommend limiting the height of the initial layer to no more than 4 feet and the thickness of the subsequent layer to no more than 3 or 4 feet. Because the fill will settle as it is placed, we recommend controlling layer thickness through depth measurements rather than surveying. The thickness should be monitored closely. Each edge after the first should be limited to 3 or 4 feet in thickness to avoid failing the embankment. It is important that the contractor not try to raise grade in excess of 4 feet; the induced settlement can cause the stages to become 5 to 6 feet thick and overstress the organic soil, resulting in failure. To properly anchor and tension the fabric, we recommend placing fill along the inner and outer edge of the strips of fabric proceeding to the middle. The advance, open “U” of the fill established with this method will help tension the fabric, mobilize available reinforcement, and control lateral and vertical deformation of the underlying organic soils. We recommend keeping the fill placement along the outer edges of the fabric approximately 30 to 50 feet ahead of the fill placed over the interior area. To permit pore water pressures in the organic soil to dissipate, we recommend that the first stage and the first half of the second stage (i.e. 6 feet) of fill consist of Select Granular Material (MnDOT 3149.2B2). For the wick drains to properly perform, it is important that sufficient gradation testing be performing of
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 21
the fill source prior and during filling operations to verify the material properties adhere to the above specification. If test results show the fine content of fill material being used exceeds the #200 sieve tolerance, the soils should be rejected. Additional fill placed at greater heights may consist of available on-site soils or common borrow. We recommend the embankment fill be compacted to 95 percent of its standard Proctor maximum dry density. Fill placed within 3 feet of the proposed pavement subgrade should be compacted to a minimum of 100 percent. A waiting period, as detailed, is recommended between stages to allow pore pressures within the buried organic soils to dissipate and permit consolidated and strengthen.
D.2.e. Embankment Monitoring
D.2.e.1. Vibrating Wire Piezometers We recommend the installation and monitoring of Vibrating Wire Piezometers (VWP) to adequately analyze groundwater response to the stage construction surcharge process. The approximate locations and elevations of the VWPs are provided in the table below. The actual location should be determined by a geotechnical engineer during installation based on the identification of the recovered soil samples. Table 11. VWP near Station 147+00
Upon termination of each borehole in the recommended location, one or more VWPs (Geokon model number 4500, or approved other) should be installed per the fully grouted method (Installation C – grout mixed to match soil conditions). Communication cables exiting the borehole should run through conduit with strain relief (or exposed and snaked, if in sand soils), to an area outside of the surcharge footprint, away from potential construction traffic or other detrimental conditions. Piezometer cables should be secured to a post, with accessible leads, to manually read the piezometer with a portable readout device (GK-404, or approved other). Alternately, piezometer cables may be connected to a post-mounted battery-powered datalogger capable of automatic data collection at 12-hour or shorter intervals (which will eliminate the need for frequent site visits). Piezometer communication cable length shall factor in sensor installation depth, distance from installation to monitoring point, associated strain relief distance, and an extra 10 feet. It is imperative that field baseline readings are gathered for each piezometer within 1 hour prior to installation, according to manufacturer recommendations. For each borehole, a VWP installation record should be prepared, including piezometer ID(s), serial number(s), date, ground elevation, borehole depth, tremie pipe length, piezometer distance from bottom of tremie pipe, tremie pipe stick up, field baseline reading, sketch of cable run, any relevant drilling installation notes, and a copy of the calibration certificate(s).
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 23
D.2.e.2. Settlement Plates To monitor cumulative and the progression of settlements caused by the fill, we recommend placing settlement plates on the base of the fill in accordance to MnDOT’s settlement plate installation guidelines. The approximate locations and elevations of the settlement plates are provided in the tables below. The settlement plates should be placed within 3 feet of the VWP locations so that settlement readings could be correlated to the pore water pressure measurements. Table 13. Settlement Plates near Station 147+00
Station Offset from Centerline
(feet) Target Soil Type Target Elevations
(feet) Remarks 146+00 0 Ground Surface 970 Within 3 feet of the VWP
146+00 25 (left) Ground Surface 970 Within 3 feet of the VWP
146+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
147+00 0 Ground Surface 970 Within 3 feet of the VWP
147+00 25 (left) Ground Surface 970 Within 3 feet of the VWP
147+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
148+00 0 Ground Surface 970 Within 3 feet of the VWP
148+00 25 (left) Ground Surface 970 Within 3 feet of the VWP
148+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
Table 14. Settlement Plates near Station 154+00
Station Offset from Centerline
(feet) Target Soil Type Target Elevations
(feet) Remarks 153+00 0 Ground Surface 970 Within 3 feet of the VWP
153+00 20 (left) Ground Surface 970 Within 3 feet of the VWP
153+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
154+00 0 Ground Surface 970 Within 3 feet of the VWP
154+00 20 (left) Ground Surface 970 Within 3 feet of the VWP
154+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
155+00 0 Ground Surface 970 Within 3 feet of the VWP
155+00 20 (left) Ground Surface 970 Within 3 feet of the VWP
155+00 35 (right) Ground Surface 970 Within 3 feet of the VWP
One-foot intervals should be marked on the riser pipes of the settlement plates to assist in controlling lift thicknesses. The riser pipe should be extended at least 10 feet above the grade and flagged so that they
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 24
can be seen by the equipment operator. If settlement causes the riser to tilt more than 10 degrees, they should be bend back to vertical. A typical sketch showing settlement plate installation is included in the Appendix.
D.2.e.3. Monitoring Pore Water Pressure and Settlement To evaluate cumulative settlement and rate of settlements, we recommend reading/surveying the piezometer and settlement plates at a minimum according to the following schedule:
� Immediately prior to the placement of each stage. � Immediately after completion of each stage. � One, 3, 7, 14 days after completion of each stage. � Biweekly reading thereafter until settlement is judged completed by a geotechnical engineer.
It is important that the survey data from each fill increment is evaluated by a geotechnical engineer before any additional fill is placed. The evaluation is required to verify that pore pressures within the foundation soils have dissipated sufficiently to avoid embankment failure and to check the amount and rate of settlement.
D.3. Pedestrian Bridge and Underpass
D.3.a. Subgrade Preparation
D.3.a.1. Subgrade Excavations Based on the borings and the proposed foundation elevations, we do not anticipate the need for a soil correction at the proposed foundation elevations. However, we recommend removal of soft saturated clays and silts below foundations if encountered during construction. Table 15 below identifies the anticipated excavation depths and bottom elevations at each boring location. Table 15. Pedestrian Bridge and Underpass Structure Excavation Depths
Location
Approximate Surface
Elevation (ft)
Anticipated Excavation
Depth (ft)
Anticipated Bottom Elevation
(ft)
Anticipated Depth Below Foundation
(ft) Underpass PMBW Bridge
C-1 1008 12 1/2 995 1/2 --- --- 0
C-2 1017 22 1/4 994 3/4 991 1/2 1003 1/2 0
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 25
We recommend having a geotechnical engineer, or an engineering technician working under the direction of a geotechnical engineer, (geotechnical representative) evaluate the suitability of exposed subgrade soils to support the proposed structure and guide the excavation. After removals and prior to the placement of engineered fill and/or foundations if required, the foundation preparation is recommended to consist of surface compacting the underlying soils and backfilling to proposed subgrade elevations with engineered backfill.
D.3.a.2. Excavation Oversizing If unsuitable materials are encountered below structures, we recommend the excavations to remove these materials be extend outward and downward at a slope of 1H:1V (horizontal:vertical) or flatter. See the figure below for a typical illustration of excavation oversizing. Figure 1. Generalized Illustration of Oversizing
1. Structural fill as defined in D.3.b 2. Excavation oversizing minimum of 1 to 1
(horizontal to vertical) slope or flatter 3. Backfill as required to meet pavement
support or landscaping requirements as defined in D.4.d
4. Backslope to OSHA requirements
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 26
D.3.a.3. Excavated Slopes Based on the borings, we anticipate on-site fill and glacially deposited soils in excavations will consist of lean clay and sandy lean clay. These soils are typically considered Type B Soil under OSHA (Occupational Safety and Health Administration) guidelines. OSHA guidelines indicate unsupported excavations in Type B soils should have a gradient no steeper than 1H:1V. Slopes constructed in this manner may still exhibit surface sloughing. OSHA requires an engineer to evaluate slopes or excavations over 20 feet in depth. An OSHA-approved qualified person should review the soil classification in the field. Excavations must comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This document states excavation safety is the responsibility of the contractor. The project specifications should reference these OSHA requirements.
D.3.a.4. Excavation Dewatering Based on the groundwater level observed in the borings and piezometer readings presented in Section B, some level of dewatering will be required to facilitate foundation installation. Based on the soil coloring observed in the borings, publically available well information and topography, the groundwater elevation obtained from the piezometer is likely perched water within the silt and sand seams trapped between confining, more cohesive soils. In an open-cut application, we would anticipate some water seeping into the excavation that could be removed with sumps and pumps. It is more likely that a perched, static water elevation is nearer the elevation where the soils transition from brown to gray. We anticipate a passive drainage system would be sufficient for tunnel design. If possible, it would be beneficial to perform some test pits during the first stage of construction to better observed the conditions likely to be encountered during tunnel construction. We recommend removing groundwater from the excavations. Sumps and pumps can be considered for excavations in low-permeability silt- and clay-rich soils, or where groundwater can be drawn down 2 feet below the bottoms of excavations in more permeable sands. In large excavations, or where groundwater must be drawn down more than 2 feet, a well contractor should review our logs to determine if wells are required, how many will be required, and to what depths they will need to be installed. Dewatering can lead to settlement of adjacent support utilities, pavements and/or structures. Therefore, we recommend the underpass structure be installed prior to other construction performed for the roadway.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 27
D.3.b. Fill Materials and Compaction In our judgment, the on-site clays are suitable for reuse as engineered fill but will likely require drying (based on the tested moisture content of the in place soils encountered) to achieve the desired compaction. To dry these soils, the contractor will need to perform extensive scarifying of these clays, which is easier to accomplish in the relatively drier months of June to September. If the contractor performs site grading in the spring or fall, on-site drying of these soils may not prove feasible and may require importing (if not available on site) drier soils or granular soils. If time or space is not available to dry these soils, the contractor may need to import (if not available on site) drier or granular soils. We recommend imported material used to replace the wet clays, consist of MnDOT Granular Material (Specification 3149.2B1). The granular bedding layer below the underpass structure is recommended to consist of Granular Bedding (MnDOT 3149.2F) and fill placed around the underpass structure should consist of Select Granular Backfill (MnDOT 3149.2D.3). We recommend spreading fill in loose lifts of approximately 8 to 12 inches thick. The project documents should not allow the contractor to use frozen material as fill or to place fill on frozen material. Frost should not penetrate under foundations during construction. We recommend compacting fill in accordance with MnDOT Specification 2105.
D.3.c. Spread Footings We understand the design team is considering supporting the underpass structure and PMBW on natural or engineered soils and the bridge abutments on Select Granular Backfill Modified 7 percent behind the PMBW. The following sections provide discussions for supporting the underpass, PMBW and pedestrian bridge on traditional ground supported footings.
D.3.c.1. Sliding Friction Angle For the Granular Bedding proposed, we recommend using an internal friction angle of 35 degrees when supporting the proposed bridge abutments on the Select Granular Backfill assuming the abutment will be design in accordance with current AASHTO LRFD specifications. D.3.c.2. PMBW Service and Strength Bearing Resistances Settlement estimates were calculated using the software program Settle3D. For the service limit state, we have used the Boussinesq method to model the stress distribution associated with the foundation load. The Boussinesq method uses the theory of elasticity to calculate the vertical stress under a strip load in, semi-infinite elastic half-space layers.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 28
We estimated the post-construction differential settlement between the underpass and the end section, and the total settlement for the stub abutments to be less than 1/2 inch. For PMBW, we analyzed the spread footings for 1 inch of construction related total settlement (service limit) for a range of foot width to generate limit state graph. The nominal service limit state line for the PMBW is included in the Appendix. For the PMBW, we estimated the nominal bearing resistances for a range of foot widths based on the information provided. The nominal bearing limit state is also included on the graph in the Appendix. For the PMBW, both the service and strength limit states should be checked to determine which limit will control the design and the controlling limit state should be used for design of the substructures. D.3.c.3. Underpass and Pedestrian Bridge Bearing Resistances We calculated the strength limit nominal bearing resistance of the structure using the methods outlined in the current AASHTO LRFD Bridge Design Specifications. The nominal bearing resistances of the underpass structure and the stub abutment of the pedestrian bridge are estimated to be 9,500 and 8,800 psf for 14- and 4-foot wide footings, respectively. No limit state graph is provided for the underpass and the pedestrian bridge stub abutments since these substructures were designed for fixed widths.
D.3.c.4. LRFD Resistance Factors For the service limit state, a resistance factor of 1.0 shall be applied. The resistance factors for evaluating the strength limit state performance for the PMBW, Underpass and Pedestrian Bridge bearing resistances provided above are based on the current AASHTO LRFD code:
� Bearing Resistance, using SPT = 0.45 � Sliding, Cast-in-Place Concrete on Sand = 0.8 � Sliding, Precast Concrete on Sand = 0.9 � Sliding, Passive Earth Pressure = 0.5
D.3.c.5. Recommended Footing Sizes and Embedment Depths The size of the PMBW footing should be determined in accordance with the limit state graphs in the Appendix. We recommend placing PMBW footings a minimum of 4 1/2 feet below the lowest grade. We recommend placing pedestrian bridge abutment footings a minimum of 4 1/2 feet below the lowest grade.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 29
D.3.c.6. PMBW Global Stability We evaluated global stability of the PMBW using computer program Slope/W, Version 8.16.1.13452, by Geo-Slope International using Spencer method by optimizing critical the slip surface. The analysis, included in the appendix, indicated the calculated factor of safety against global failure met or exceeded the target factor of safety of 1.5.
D.4. Pavement Subgrade Preparation
D.4.a. Excavations Outside of the swamp deposit areas, we recommend removing fill, topsoil and organic soils prior to roadway subgrade placement. Based on the boring logs, excavation depths are expected to range from approximately 2 to 4 feet below existing grade. Excavation depths will vary between the boring locations. Portions of the excavations may also be deeper than indicated by the boring logs. Contractors should also be prepared to extend excavations in wet or fine-grained to remove disturbed bottom soils. Surficial soils can be mistaken for topsoil, particularly when they are wet. Accordingly, we recommend an engineer or his representative be present during stripping to document appropriate depths of topsoil (and organic soils) are stripped. To provide lateral support to replacement backfill and additional required fill, we recommend oversizing (widening) the excavations 1 foot horizontally beyond the outer edges of the pavement limits, for each foot the excavations extend below pavement subgrade elevations.
D.4.b. Excavation Dewatering If excavations for pavement support extend below groundwater, we recommend dewatering procedures detailed in Section D.3.a.4 be followed.
D.4.c. Selecting Excavation Backfill and Additional Required Fill We initially recommend backfilling over wet or submerged excavation bottoms with at least 2 feet of coarse sand having less than 50 percent of the particles by weight passing a #40 sieve, and less than 5 percent of the particles passing a #200 sieve. We anticipate that this material will need to be imported.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 30
On-site soils free of organic soil and debris can be considered for reuse as backfill and fill. The glacial till soils and other fine-grained soils will be more difficult to compact in their present wet condition or if they are allowed to become wet. It will be necessary to moisture condition (dry) these soils from their present state for efficient compaction in the moisture ranges indicated in Table 16 below. We recommend that granular subbase material for pavement support consist of sand having less than 20 percent of the particles by weight passing a #200 sieve. We anticipate that this material will need to be imported. Imported soil needed to replace excavation spoils or balance cut and fill quantities, may consist of sand, silty sand, clayey sand, sandy lean clay or lean clay. We recommend, however, that the plastic index (an indication of the clayey nature of the soils) of these materials not exceed 15.
D.4.d. Placement and Compaction of Backfill and Fill We recommend spreading backfill and fill in loose lifts of approximately 12 inches. We recommend compacting backfill and fill in accordance with the criteria presented below in Table 16. The relative compaction of utility backfill should be evaluated based on the structure below which it is installed, and vertical proximity to that structure. Table 16. Compaction Recommendations Summary
Reference Relative Compaction, percent
(ASTM D 698 – standard Proctor) Moisture Content Variance from
Optimum, percentage points
Below pavements, within 3 feet of subgrade elevations
100 +/- 3
Below pavements, more than 3 feet below subgrade elevations
95 +/- 3
Below landscaped surfaces 92 +/- 3
D.5. Pavements
D.5.a. Subgrade Proofroll Prior to placing aggregate base material, we recommend proofrolling pavement subgrades to determine if the subgrade materials are loose, soft or weak, and in need of further stabilization, compaction or subexcavation and recompaction or replacement. A second proofroll should be considered after the aggregate base material is in place, and prior to placing bituminous or concrete pavement.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 31
D.5.b. Recommended R-Value Laboratory samples for the purpose of R-value tests for pavement design were not in our scope of services as part of this exploration. For R-value design, we referenced Table 5-3.2(a) of the MnDOT Geotechnical and Pavement Design Manual. Based on the soils encountered in the boring logs, typical values from Table 5-3.2(a), and our experience with similar projects in the area, it is our opinion that an R-value of 12 can be assumed for design purposes.
D.5.c. Subgrade Drainage We recommend installing perforated drainpipes throughout pavement areas at low points and about catch basins. The drainpipes should be placed in small trenches extended at least 8 inches below the granular subbase layer – or aggregate base material where no subbase is present.
D.6. Construction Quality Control
D.6.a. Excavation Observations We recommend having a geotechnical engineer observe all excavations related to subgrade preparation and spread footing, slab-on-grade and pavement construction. The purpose of the observations is to evaluate the competence of the geologic materials exposed in the excavations, and the adequacy of required excavation oversizing.
D.6.b. Materials Testing We recommend density tests be taken in excavation backfill and additional required fill placed below spread footings, slab-on-grade construction, beside foundation walls behind basement walls, and below pavements. We recommend Gyratory tests on bituminous mixes to evaluate strength and air voids, and density tests to evaluate compaction. We also recommend slump, air content and strength tests of Portland cement concrete.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 32
D.6.c. Pavement Subgrade Proofroll We recommend that proofrolling of the pavement subgrades be observed by a geotechnical engineer to determine if the results of the procedure meet project specifications, or delineate the extent of additional pavement subgrade preparation work.
D.6.d. Cold Weather Precautions If site grading and construction is anticipated during cold weather, all snow and ice should be removed from cut and fill areas prior to additional grading. No fill should be placed on frozen subgrades. No frozen soils should be used as fill. Concrete delivered to the site should meet the temperature requirements of ASTM C 94. Concrete should not be placed on frozen subgrades. Concrete should be protected from freezing until the necessary strength is attained. Frost should not be permitted to penetrate below footings.
E. Utilities We anticipate the soils at typical invert elevations outside the swamp crossing will be suitable for utility support. If construction encounters unfavorable conditions such as soft clay, organic soils, peat or perched water at invert grades, the unsuitable soils may require additional subcutting and replacement with sand or crushed rock to prepare a proper subgrade for pipe support. All utilities within the swamp crossing should be designed to accommodate a differential settlement of 6 inches when installed near the embankment and 12 inches if installed across the embankment. We anticipate the maximum differential settlement to occur near the edges of the swamp where ground surface dips into the swamp. Project design and construction should not place utilities within the 1H:1V oversizing of foundations for retaining walls, or casing may be necessary. Based on our experience, the soils encountered by the borings are moderately corrosive to metallic conduits, but only marginally corrosive to concrete. We recommend specifying non-corrosive materials or providing corrosion protection, unless additional tests demonstrate the soils are not corrosive.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 33
F. Construction Equipment Support The recommendations included in the report may not be applicable to equipment used for the construction of this project. We recommend evaluating subgrade conditions in areas of shoring, cranes, pumps and other construction equipment prior to mobilization to determine if the foundation materials are suitable for equipment support, or require some form of subgrade improvement. We also recommend project planning consider the effect that loads applied by such equipment may have on structures they bear on or surcharge – including pavements, buried utilities, retaining walls, etc.
G. Procedures
G.1. Penetration Test Borings The penetration test borings were drilled with a floatation or track-mounted auger drill equipped with hollow-stem auger. The borings were performed in accordance with ASTM D 1586. Penetration test samples were taken at 2 1/2- or 5-foot intervals. Actual sample intervals and corresponding depths are shown on the boring logs. We collected thin-walled tube samples in general accordance with ASTM D1587 at selected depths. The boring logs show the actual sample intervals and corresponding depths. We sealed penetration test boreholes meeting the Minnesota Department of Health (MDH) Environmental Borehole criteria with an MDH-approved grout.
G.2. Cone Penetration Test Soundings We performed CPT soundings by advancing a 1.75-inch diameter seismic piezocone with an unequal end area ratio of 0.8. We used a 20-ton track-mounted rig to advance the cone into the ground. We performed the soundings in general accordance with ASTM D5778. While advancing the cone, we digitally recorded tip resistance (Qt), sleeve friction (FS) and pore pressure (U2).
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 34
G.3. Power Auger borings We performed the power auger borings with the same equipment as our penetration test borings and in general accordance with ASTM D1452. We inferred the soil classifications and strata depths from the cuttings brought to the surface by rotation of the auger. At desired depths, we placed auger cuttings in bags and jars.
G.4. Material Classification and Testing
G.4.a. Visual and Manual Classification We visually and manually classified the geologic materials encountered for this investigation in accordance with ASTM Standard Practice D 2488. The Appendix includes a chart explaining the classification system. Samples were placed in jars, thin wall tubes or bags and returned to our facility for review and storage.
G.4.b. Laboratory Testing The exploration logs in the Appendix note most of the results of the laboratory tests performed on geologic material samples. The remaining laboratory test results follow the exploration logs. We performed the tests in general accordance with ASTM or AASHTO procedures.
G.5. Groundwater Measurements The drillers checked for groundwater while advancing the penetration test borings, and again after auger withdrawal. We then filled the boreholes or allowed them to remain open for an extended period of observation, as noted on the boring logs. We also inferred groundwater levels from pore pressure measurements made during advancement of the piezocone.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 35
H. Qualifications
H.1. Variations in Subsurface Conditions
H.1.a. Material Strata We developed our evaluation, analyses and recommendations from a limited amount of site and subsurface information. It is not standard engineering practice to retrieve material samples from exploration locations continuously with depth. Therefore, we must infer strata boundaries and thicknesses to some extent. Strata boundaries may also be gradual transitions, and project planning should expect the strata to vary in depth, elevation and thickness, away from the exploration locations. Variations in subsurface conditions present between exploration locations may not be revealed until performing additional exploration work, or starting construction. If future activity for this project reveals any such variations, you should notify us so that we may reevaluate our recommendations. Such variations could increase construction costs, and we recommend including a contingency to accommodate them.
H.1.b. Groundwater Levels We made groundwater measurements under the conditions reported herein and shown on the exploration logs, and interpreted in the text of this report. Note that the observation periods were relatively short, and project planning can expect groundwater levels to fluctuate in response to rainfall, flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal and annual factors.
H.2. Continuity of Professional Responsibility
H.2.a. Plan Review We based this report on a limited amount of information, and we made a number of assumptions to help us develop our recommendations. We recommend retaining us to review the geotechnical aspects of the designs and specifications. This review will allow us to evaluate whether we anticipated the design correctly, if any design changes affect the validity of our recommendations, and if the design and specifications correctly interpret and implement our recommendations.
Bolton & Menk, Inc. Project B1608361 March 27, 2017 Page 36
H.2.b. Construction Observations and Testing We recommend retaining us to perform the required observations and testing during construction as part of the ongoing geotechnical evaluation. This will allow us to correlate the subsurface conditions exposed during construction with those encountered by the borings, and to provide professional continuity from the design phase to the construction phase. If we are not retained, it becomes the responsibility of others to validate the assumption made during the preparation of this report and to accept the construction-related geotechnical engineer-of-record responsibilities.
H.3. Use of Report This report is for the exclusive use of the addressed parties. Without written approval, we assume no responsibility to other parties regarding this report. Our evaluation, analyses and recommendations may not be appropriate for other parties or projects.
H.4. Standard of Care In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under similar circumstances by reputable members of its profession currently practicing in the same locality. No warranty, express or implied, is made.
Drilling NotesStandard penetration test borings were advanced by 3 1/4” or 6 1/4”ID hollow-stem augers unless noted otherwise, Jetting water was usedto clean out auger prior to sampling only where indicated on logs.Standard penetration test borings are designated by the prefix “ST”(Split Tube). All samples were taken with the standard 2” OD split-tubesampler, except where noted.
Power auger borings were advanced by 4” or 6” diameter continuous-flight, solid-stem augers. Soil classifications and strata depths were in-ferred from disturbed samples augered to the surface and are, therefore,somewhat approximate. Power auger borings are designated by theprefix “B.”
Hand auger borings were advanced manually with a 1 1/2” or 3 1/4”diameter auger and were limited to the depth from which the auger couldbe manually withdrawn. Hand auger borings are indicated by the prefix“H.”
BPF: Numbers indicate blows per foot recorded in standard penetrationtest, also known as “N” value. The sampler was set 6” into undisturbedsoil below the hollow-stem auger. Driving resistances were then countedfor second and third 6” increments and added to get BPF. Where theydiffered significantly, they are reported in the following form: 2/12 for thesecond and third 6” increments, respectively.
WH: WH indicates the sampler penetrated soil under weight of hammerand rods alone; driving not required.
WR: WR indicates the sampler penetrated soil under weight of rodsalone; hammer weight and driving not required.
Note: All tests were run in general accordance with applicable ASTMstandards.
Particle Size IdentificationBoulders ............................... over 12”Cobbles ............................... 3” to 12”Gravel
Coarse ............................ 3/4” to 3”Fine ................................. No. 4 to 3/4”
SandCoarse ............................ No. 4 to No. 10Medium ........................... No. 10 to No. 40Fine ................................. No. 40 to No. 200
Silt ....................................... No. 200, PI 4 or below “A” line
Clay ..................................... No. 200, PI 4 and on or above “A” line
Relative Density of Cohesionless Soils
Very loose ................................ 0 to 4 BPFLoose ....................................... 5 to 10 BPFMedium dense ......................... 11 to 30 BPFDense ...................................... 31 to 50 BPFVery dense ............................... over 50 BPF
Consistency of Cohesive SoilsVery soft ................................... 0 to 1 BPFSoft ....................................... 2 to 3 BPFRather soft ............................... 4 to 5 BPFMedium .................................... 6 to 8 BPFRather stiff ............................... 9 to 12 BPFStiff ....................................... 13 to 16 BPFVery stiff ................................... 17 to 30 BPFHard ....................................... over 30 BPF
a. Based on the material passing the 3-in (75mm) sieve.b. If field sample contained cobbles or boulders, or both, add “with cobbles or boulders or both” to group name.c. Cu = D60 / D10 Cc = (D30)
2
D10 x D60
d. If soil contains 15% sand, add “with sand” to group name.e. Gravels with 5 to 12% fines require dual symbols:
GW-GM well-graded gravel with siltGW-GC well-graded gravel with clayGP-GM poorly graded gravel with siltGP-GC poorly graded gravel with clay
f. If fines classify as CL-ML, use dual symbol GC-GM or SC-SM.g. If fines are organic, add “with organic fines” to group name.h. If soil contains 15% gravel, add “with gravel” to group name.i. Sands with 5 to 12% fines require dual symbols:
SW-SM well-graded sand with siltSW-SC well-graded sand with claySP-SM poorly graded sand with siltSP-SC poorly graded sand with clay
j. If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.k. If soil contains 10 to 29% plus No. 200, add “with sand” or “with gravel” whichever is predominant.l. If soil contains 30% plus No. 200, predominantly sand, add “sandy” to group name.m. If soil contains 30% plus No. 200 predominantly gravel, add “gravelly” to group name.n. PI 4 and plots on or above “A” line.o. PI 4 or plots below “A” line.p. PI plots on or above “A” line.q. PI plots below “A” line.
Poorly graded sand h
Peat
Well-graded gravel d
PI plots on or above “A” line
PI 7 and plots on or above “A” line j
PI 4 or plots below “A” line j
Fine
-gra
ined
Soi
ls50
% o
r mor
e pa
ssed
the
No.
200
sie
ve
Coa
rse-
grai
ned
Soils
mor
e th
an 5
0% re
tain
ed o
nN
o. 2
00 s
ieve
Soils Classification
GravelsMore than 50% of
coarse fractionretained onNo. 4 sieve
Sands50% or more ofcoarse fraction
passesNo. 4 sieve
Silts and ClaysLiquid limit
less than 50
Highly Organic Soils
Silts and claysLiquid limit50 or more
Primarily organic matter, dark in color and organic odor
GroupSymbol
Criteria for Assigning Group Symbols andGroup Names Using Laboratory Tests a
Group Name b
GW
GPGMGCSWSPSM
CLMLOLOL
SC
Poorly graded gravel d
Silty gravel d f g
Clean Gravels5% or less fines e
Gravels with FinesMore than 12% fines e
Clean Sands5% or less fines i
Sands with FinesMore than 12% i
Fines classify as ML or MHFines classify as CL or CH Clayey gravel d f g
Well-graded sand h
Fines classify as CL or CHFines classify as ML or MH Silty sand f g h
Clayey sand f g h
Inorganic
Organic Liquid limit - oven driedLiquid limit - not dried
0.75
Inorganic
Organic
PI plots below “A” line
Lean clay k l m
Liquid limit - oven driedLiquid limit - not dried
0.75
CHMH
OHOH
Fat clay k l m
Elastic silt k l m
Organic clay k l m n
Organic silt k l m o
Organic clay k l m p
Organic silt k l m q
Cu 6 and 1 Cc 3 C
PT
Cu 4 and 1 Cc 3 C
Cu 4 and/or 1 Cc 3 C
Cu 6 and/or 1 CC 3 C
0 10 16 20 30 40 50 60 70 80 90 100 110
7
“U” L
ine
“A” Line
10
20
30
40
50
60
4 0
ML or OL
MH or OHCL or O
L
CH or O
H
CL - ML
Silt k l m
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
15.6
2 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
75.4
6 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5410
.21,
Y:1
7283
0.68
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: R
-1
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
4 AM
1Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
15.6
0 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
88.8
4 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5116
.53,
Y:1
7215
6.47
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: R
-2
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
5 AM
2Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
56.5
8 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
68.2
0 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5262
.72,
Y:1
7242
5.93
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-01
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
5 AM
3Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
40.6
3 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
69.1
2 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5190
.51,
Y:1
7244
8.87
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-02
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
5 AM
4Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
40.5
5 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
71.4
2 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5114
.48,
Y:1
7247
3.37
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-03
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
5 AM
5Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
40.0
3 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
69.1
5 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5307
.29,
Y:1
7254
6.33
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-04
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
6 AM
6Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
56.4
2 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
69.1
7 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5238
.79,
Y:1
7257
6.35
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-05
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
6 AM
7Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
50.0
9 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
69.9
9 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5165
.62,
Y:1
7260
5.96
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-06
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
6 AM
8Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
24.3
0 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
73.3
6 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5539
.77,
Y:1
7303
5.43
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-07
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
6 AM
9Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
30.4
1 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
71.5
5 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5614
.37,
Y:1
7300
2.27
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-08
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
7 AM
10Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
30.5
4 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
72.1
6 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5561
.24,
Y:1
7305
5.09
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-09
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
7 AM
11Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
30.2
7 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
72.8
0 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5502
.45,
Y:1
7311
0.84
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-10
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
7 AM
12Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
30.3
1 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
70.5
8 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5705
.95,
Y:1
7309
6.26
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-11
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
7 AM
13Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
Pro
ject
:C
SAH
10
Wes
t R
ing
Roa
dBra
un I
nter
tec
Cor
pora
tion
1100
1 H
amps
hire
Ave
SM
inne
apol
is, M
N 5
5438
952-
995-
2000
Tota
l dep
th:
37.2
0 ft
, Dat
e: 1
/10/
2017
Surf
ace
Elev
atio
n: 9
70.0
2 ft
Wac
onia
, MN
Pro
ject
Num
ber:
B16
0836
1
Coor
ds:
X:48
5594
.09,
Y:1
7320
3.01
Cone
Typ
e: S
CPTu
458
3.12
1.B
Cone
Ope
rato
r: H
olm
bo
CP
T: S
-12
Loca
tion
:
CPeT
-IT
v.1.
7.6.
42 -
CPT
U d
ata
pres
enta
tion
& in
terp
reta
tion
soft
war
e -
Repo
rt c
reat
ed o
n: 1
/20/
2017
, 10:
42:1
7 AM
14Pr
ojec
t fil
e: C
:\U
sers
\tre
ich\
Des
ktop
\CPE
TIT.
cpt
2/2010
This document accompanies Cone Penetration Test Data. Please refer to the Boring Log Descriptive Terminology Sheet for information relevant to conventional v. Cone Penetration Test (CPT) boring logs. Cone Penetration Test (CPT) sounding was performed in general accordance with ASTM D 5778 and consistent with the ordinary degree of care and skill used by reputable practitioners of the same discipline currently practicing under similar circumstances and in the same locality. No warranty, express or implied, is made. Since subsurface conditions outside each CPT sounding are unknown, and soil, rock and pore water conditions cannot be relied upon to be consistent or uniform, no warranty is made that conditions adjacent to each sounding will necessarily be the same as or similar to those shown on this log. Braun Intertec is not responsible for any interpretations, assumptions, projections or interpolations of the data made by others. Pore water pressure measurements and subsequently interpreted water levels shown on CPT logs should be used with discretion as they represent dynamic conditions. Dynamic pore water pressure measurements may deviate substantially from hydrostatic conditions, especially in cohesive soils. In cohesive soils, pore water pressures often take an extended time to reach equilibrium and thus reflect their true field level. Groundwater levels can be expected to vary both seasonally and yearly. The absence of notations on this log regarding water does not necessarily mean that groundwater is not present to the depth explored, or that a contractor will not encounter groundwater during excavation or construction. CPT Terminology CPT ............ Cone Penetration Test CPTU ......... Cone Penetration Test with Pore Pressure measurements SCPTU ....... Cone Penetration Test with Pore Pressure and Seismic measurements Piezocone...Common name for CPTU test QT ........................ normalized cone resistance Bq ......................... pore pressure ratio Fr .......................... normalized friction ratio σvo ........................ overburden pressure σ’vo ....................... effective overburden pressure qT TIP RESISTANCE The resistance at the cone corrected for water pressure. Data is from cone with a 60 degree apex angle and a 15 cm2 end area. fs SLEEVE FRICTION RESISTANCE The resistance along the sleeve of the penetrometer. Fr Friction Ratio Ratio of sleeve friction over corrected tip resistance. Fr = fs/qt Vs Shear Wave Velocity A measure of the speed at which a seismic wave travels through soil/rock.
SBT SOIL BEHAVIOR TYPE Soil Identification methods for the Cone Penetration Test are based on correlation charts developed from observations of CPT data and conventional borings. Please note that these identification charts are provided as a guide to Soil Behavior Type and should not be used to infer a soil classification based on grain size distribution. Engineering judgment and comparison with augered borings is especially important in the proper interpretation of CPT data in certain geo-materials. The following charts provide a Soil Behavior Type for the CPT Data. The numbers corresponding to different regions on the charts represent the following soil behavior types: Soil Behavior Type based on friction ratio
Robertson CPT 1990
Soil Behavior Type based on pore pressure
Robertson CPT 1990
1 Sensitive, Fine Grained 2 Organic Soils - Peat 3 Clays - Clay to Silty Clay 4 Silt Mixtures - Clayey Silt to Silty Clay 5 Sand Mixtures - Silty Sand to Sandy Silt 6 Sands - Clean Sand to Silty Sand 7 Gravelly Sand to Sand 8 Very Stiff Sand to Clayey Sand 9 Very Stiff, Fine Grained U2 PORE WATER MEASUREMENTS Pore water measurements reported on CPT logs are representative of pore water pressures measured at the U2 location, just behind the cone tip, prior to the sleeve, as shown in the figure below. These measurements are considered to represent dynamic pore water pressures due to the local disturbance caused by the cone tip. Dynamic pore water pressure decay and static pore water pressure measurements are reported on a Pore Water Pressure Dissipation Graph.
Descriptive Terminology Cone Penetration Test
%Gr.Moist.Sat.eo
Swell Press.CcPcOverburdenSp.PILLDry Dens.Natural
Project:
Remarks:Client:Project No.
AASHTOUSCSMATERIAL DESCRIPTION
CONSOLIDATION / SWELL TESTING
.1 .2 .5 1 2 5 10 20.32
.36
.40
.44
.48
.52
.56
.60
.64
.68
.72V
oid
Rat
io
Applied Pressure - tsf
(tsf)(tsf)(tsf)(pcf)SwellCr
1
ASTM D 2435CSAH 10 West Ring RoadCSAH between 102nd Street and Waconia Parkway, Waconia, MN
