Narrows Marine Crossing

REALISING A VISION BY INNOVATING EXCELLENCE

The 12th Australian Tunnelling Conference 21st November, 2013

Andrew Axton (GLNG) Scott Connor (Thiess)

GLNG PIPELINE

OVERVIEW The GLNG Pipeline is a 420 km long 1050 mm diameter gas transmission pipeline running from Fairview to Curtis Island, for the transportation of gas from fields in the Roma, Fairview and Arcadia Valley area across the Callide Range and across the Narrows Channel to Curtis Island.

PROJECT STATISTICS:

•  420 km’s

•  92 land deeds

•  265 Water Courses to cross

•  51 classed as major

•  2 State Development Areas (SDAs) to cross

•  Run parallel with the other Proponents Pipelines

•  Narrows crossing

•  3 camps

•  6 stockpile locations on the route

•  2 stockpile locations at the Ports

TYPICAL PIPELINE CONSTRUCTION SPREAD

CONSTRUCTION ACTIVITY

Clear and Grade Stringing Bending

Pipe Welding

Excavation / Trenching Lower In Bedding and Padding

Restoration / Rehabilitation

PIPELINE

Legend: Clearing Trenching Welding FJC Lowering Backfilling Rehabilitation

Watercourse crossings major

Trenching Across Mudflats

Offshore Trenching (Dredging)

Major Creek Crossing

ORIGINAL CROSSING

METHODOLOGY - TRENCHING

Concept: HDDs (4 drives) & Marine access

2ND ITERATION CROSSING

METHODOLOGY - HDD

3RD ITERATION CROSSING

METHODOLOGY - DIRECT PIPE

Tunnel / Pipeline

Receptor Pad

Launch Pad

Access Road

Mainland Trenched Pipeline

Minor Creek Crossings

TUNNEL CROSSING

METHODOLOGY

OTHER PROPONENTS

METHODOLOGY 1 OF 3

OTHER PROPONENTS

METHODOLOGY 2 OF 3

OTHER PROPONENTS

METHODOLOGY 3 OF 3

CONTRACT DATES

EPC PIPELINE CONTRACT AWARDED TO SAIPEM JUNE 2011

OPTIONEERING CROSSING METHODOLOGY JUNE 2011- MAY 2012

VARIATION GRANTED TO SAIPEM FOR TUNNEL- MAY 2012

SAIPEM AWARD TUNNELLING CONTRACT TO THIESS- SEPTEMBER 2012

GLNG FORMED ‘OWNER’S ENGINEERING TEAM’ (GHD) TO OVERSEE CONSTRUCTION

THIESS COMMENCED CONSTRUCTION OCTOBER 2012

Handover to Andreas

•  Early 2012, contacted to discuss options for a SUBTERRANEAN CROSSING

•  HDD vs. DP vs. TBM

•  Highest safety and environmental standards

•  Minimal footprint

•  42 year operational life

•  Fast track delivery

•  Integrated project partner

UNDERSTANDING THE VISION

•  Start tunnelling within 12 months of feasibility study

•  Minimal geotech / bathymetry data available

•  Extremely compressed design, procurement and construction schedule

•  Developing a “best-for-project” solution

EARLY CHALLENGES

INITIALLY PROPOSED: Alignment •  Maintain 2d cover except at

entry/exit locations •  Minimise grade •  Minimise length   The problem? Too little

geotech Site layout •  Shaft operation with gantry

crane •  Pipes stringed on adjacent site

and fed into tunnel via 1:7 ramp (constructed on critical path)

  The problem? Slow and riskier operation

REALISING THE VISION CHALLENGES OF

TURNING AN IDEA INTO ‘READY TO BORE’ IN

12 MONTHS

•  Early assessment conducted o Single-beam bathymetry

o Continuous seismic profiling (CSP)

o Underwater seismic refraction (USR)

o Land seismic refraction (LSR)

•  Borehole drilling on mainland site

•  Later marine investigation

•  Final revalidation of all design assumptions after g.I. Complete (GDR)

REALISING THE VISION OVERCOMING THE GEOTECH

CHALLENGE

Composite seismic section beneath channel

CSP Section beneath mudflats

REALISING THE VISION FINAL GEOTECH BASELINE

  THE SOLUTION?

Integrated site layout

•  Turn shaft into 400m decline

•  Pipe stringing adjacent to decline

•  Rapid TBM rolling stock support without rushing

•  Rapid pipe install

REALISING THE VISION INTEGRATING THE

SOLUTION TO INCREASE EFFICIENCY

Final Integrated Site Layout – Tunnelling and Pipe Install

Original “Tunnelling Dedicated” Site

Concept Integrated solution

Fully integrated launch shaft design • Improved TBM launch • Improved TBM production • Improved pipe installation • Safer • TBM thrust foundations combined with pipe thruster

REALISING THE VISION INTEGRATING THE

SOLUTION Concept

Integrated solution

REALISING THE VISION CLIENT/CONTRACTOR

INTEGRATED SOLUTION

•  Conservative approach – adjusted as data arrived

•  Experienced designers familiar with the scope

•  Collaborative design reviews

•  Continual refinement

•  Alignment example o Used initial data to drop

concept alignment

o Used final borehole to raise exit point

REALISING THE VISION OVERCOMING THE DESIGN

‘NO TIME, NO DATA’ CHALLENGE

8m

3m

Example: Alignment

Low-point BEFORE

Low-point AFTER

350m

•  Procured and reconditioned 4.05m EPB TBM (herrenknecht) and matching moulds

•  Selective approach to early procurement of critical items – eg, new TBM cutterhead, additional TBM capability (grouting, slurry mode), rolling stock, mould refurb.

•  Offsite TBM commissioning, for quick build and launch on site

REALISING THE VISION OVERCOMING THE

PROCUREMENT CHALLENGE

As at November 2013 • 3600m complete • Traversed past low point - commenced incline to island • 125m/wk average vs 95m/wk target • Reception shaft complete

REALISING THE VISION PROGRESS TO DATE

REALISING THE VISION

EPB successful - geotech predominantly stiff sandy clay

• 300m traverse of fault – gravels

• Areas of high permeability

• Use of ground treatment chemicals critical: foam, polymer, bentonite

Communication is the key to delivering fast track project

CHALLENGES AND LESSONS LEARNT

TO DATE

Handback from Andreas

POST

BREAKTHROUGH

ACTIVITIES

•  INSTALLATION OF FOC

•  INITIAL FLOOD OF TUNNEL

•  PIPE PUSHING OPERATION

•  HYDRO-TESTING OF PIPE

•  CONSTRUCTION OF END PLUGS

•  SECONDARY FLOOD OF TUNNEL

•  BACKFILL AND REINSTATEMENT

Typical Cross section (Operation)

FLOODING OF TUNNEL

•  TUNNEL TO BE FILLED WITH SEAWATER

•  OFFSHORE PUMPING FROM PONTOON ANCHORED TO SEABED

•  EA AMENDMENT FOR EXTRACTION

•  3 DAY OPERATION •  40,000M3 •  250L/SEC PUMP RATE •  SCREENING TO 1MM

PIPE PUSHING OPERATION

•  FABRICATE PIPE STRINGS APPROXIMATELY 216M IN LENGTH

•  THRUST INTO TUNNEL VIA PIPE ROLLERS

•  750 TONNE HERRENKNECHT PIPE THRUSTER

•  5M STROKE 6MIN STROKE TIME

•  1 MIN RETRACTION TIME

•  216M IN 6 HOURS

Roller-way Arrangement

Roller way arrangement - plan view and longitudinal section

Pipe Roller typical sections

Pipe launch head detail

PIPE INSTALLATION

AERIAL STRINGING YARD

Tunnel Centreline Triple Joint

Prefabrication Yard

GTP Right-of-Way

Service Crane Way

Offices Area

Welding Stations at

36m Centres

or Welding train

Pipe Thruster

Mainland Curtis Island

END PLUG DESIGN

STATS • MAINTAIN SEAWATER LEVEL INTO TUNNEL @RL-2.47M • 83.35M MAINLAND TUNNEL PLUG • 20M CURTIS ISLAND PLUG • 10MPA CONCRETE FLOWABLE FILL • 823M3 OF CONCRETE • 5 STAGE BACKFILL TO PREVENT FLOATATION

Mainland

BACKFILL AND REINSTATEMENT

Curtis Island

GLADSTONE’S LEGACY

•  ASH FROM GLADSTONE POWER STATION OVER 30 YEARS RECLAIMED SECTION OF TIDAL MUD FLATS

•  LAND GIFTED TO GLADSTONE REGIONAL FOR REHABILITATION

•  TUNNEL SPOIL TO FORM 500MM CAPPING LAYER TO THE POND

•  FUTURE RECREATIONAL OR SPORT FIELD USAGE

Fill Material Lime Guard Layer (min 5kg/m2)

Existing Ash

•  THIESS CONTRACT – TIP AND GO

•  GLNG FORMED A COST REIMBURSABLE CONTRACT WITH GRC TO ALLOW TIPPING TO COMMENCE

•  CONTRACT COVERED TOPSOIL STRIPPING, DRYING, SPREADING AND COMPACTING TUNNEL SPOIL AND REPLACING THE TOPSOIL, READY FOR SEEDING

ASHPOND CAPPING

OCTOBER 2013

QUESTIONS?