Crossrail C310 Thames Tunnel

Home , London City Airport, Thames Tunnel, Woolwich Ferry

CROSSRAIL C310 THAMES TUNNEL Geotechnical & tunneling related specifics in urban tunneling & a river crossing with low overburden.

Dr. Taner AYDOGMUS, Technical Director Riku Tauriainen, MSc., Project Director Frank Wiegand, MSc., Technical and Risk Manager

OUTLINE 1. Project Overview 2. Challenges 3. River Crossing 4. Design Elements 5. Summary

Tunnel btw. Plumstead and Woolwich Box

CROSSRAIL Project – Moving London Forward

• Crossrail is a rail line that will run from Reading and Heathrow Airport in the West, through new twin-bore tunnels under central London to Shenfield and Abbey Wood in the East;

• Total 118km (73mile) new railway, 42km (26mile) tunnels and 40 stations of which 8 will be subterranean;

• It will bring an additional 1.5 million people within 45 minutes commuting distance of London's key business districts and increase London's rail-based transport network capacity by 10%;

• Overall 8 TBMs in operation (6 EPB + 2 Mix-shield);

• Investment approx. £14.8 Billion = $19.5 Billion (excluding “Rolling Stock”).

Tunnel Alignment & Portals

Thames N

London City Airport

North Woolwich Belmarsh Portal River Thames

Woolwich Box Plumstead Portal

Tunnel Alignment & Portals

North Woolwich Thames Barrier Portal City Airport

Woolwich Box

Belmash Prison

Plumstead Portal

Tunnel Alignment & Portals

Thames Barrier

North Woolwich City Airport Portal

Geotechnical Conditions

North Woolwich Cover Woolwich Cover Plumstead Portal ca. 12m (39.3’) Box ca. 20m (65.6’) Portal

10m GWL

CP 19 CP 16 CP 18 + Pump Sump CP 17 + Pump sump

TBM Drive Direction

TBM Selection

• Contract allowed for both Mix-Shield & EPB Technology • Decision was based on risk assessment: – Low overburden – Geology – Settlements – Chalk disposal – Program security – Cost • Mix-Shield technology is more expensive but in overall scoring of risk assessment Mix-Shield “Sophia” at factory acceptance July 2012 outperformed EPB

Programme

• Procurement – 03/18/2011 • TBM Breakthrough – 05/13/2014 • Completion – 06/10/2015

Advantages of TBM Reception with sealing pot: • no grout block – one slurry wall panel only • no risks of leak by means blow off the compressed air when run in the sealing • reusable

Challenges at Plumstead Portal

• Close proximity to Operational Railway;

• Unknown utilities, Marmadon Road Sewer;

• White Hart Road Bridge;

• Sensitive Equipment within Cathedral Substation;

• Cross Passage CP19 low Chalk overburden;

Ground Engineering Techniques for Portal Construction

60m (197’) CFA piles

Secant Wall (Cased CFA)

180m (591’) Secant Pile Wall 193m (633’) Diaphragm Walls (cased) 18m (59’) depth up to 22m (72’) depth

Tension Piles / Rotary Bored Piles up to 38m (125’) depth

Four Piling Rigs & Five Attendant Cranes at One Time

Top-Down Construction of Portals

• Internal dewatering • Recharge outside of portal foot print • Two levels of temporary propping • Bulk excavation • Portal in-situ concrete slab Dewatering well • Real time monitoring

Hydraulic temporary propping

Lifting Operations Next to Operating Railway Line

Risk: proximity of the portal works to the Network Rail (NR): • >3m (9.8’) away from a running line; not compliant with existing NR regulations;

700 to crane at headwall • Trains one every 3 minutes; • 8 months to develop a workable solution w/ NR; • Slew restrictions; • Reinforced concrete piling

Tandem lift – D-wall platform; cage • 3 full-time protection staff on rail line & automatic crane collapse alarms.

Deep Excavation in Close Proximity to Operational Railway

Shape Accelerator Arrays (SAA) in D-wall

• show real time movement of the box structures over the full depth;

• Effects of Dewatering, Excavation, Props and structural loading of area adjacent to box.

SAA strand in D-wall

TBM Tunneling Interface at Cathedral Substation

Cathedral Substation

Compensation Grouting at Cathedral Substation Low overburden, Gravel and below GW

GW - 6.0m 4.5m Gravel (19.6’) (14.8’) Lev el

Grout Shaft

TAM Drillings

Challenges at North Woolwich Portal

• Late site possession due to complicated service diversions on the portal footprint;

• Risk of cross contamination due to dewatering and recharge operations for portal excavation;

• Sheet piles extending into the tunnel envelope below a 2.4m (7.9’) Thames Water sewer;

Store Road Sheet Pile Removal

TW Pumping Station

Sheet piles extending to tunnel envelope

Store Road Sheet Pile Removal Existing pipe demolition New Cofferdam

Removal old sheet piles New DN 2.4m (7.9’) pipe installation

River Crossing

• Tunnel length underneath Thames approx. 480m (1,574’) (between flood Woolwich Box protection walls);

Flood Protection Walls • Approx. 300 rings CP 17 to build underneath Woolwich Ferry Thames;

• Cross Passage CP17 to build underneath North Woolwich Portal Thames.

First Thames Tunnel by Marc Brunel – 1826 to 1846

Brunel‘s Tunnel, 1828 (Mathewson)

River Crossing – Tidal Impact

Closed Face Mixshield TBM with Double Chamber • Control of Face- pressure • Reduction of Settlements

Slurry Balance 1. Submerged Wall. Control 2. Working Chamber. 3. Air Cushion. 4. Pressure bulkhead.

River Crossing – Tidal Impact Real Time Data from River Thames, Damping effect in Chalk

Variation of tide approx. 8m (26.2’)

2 tide cycles in 24 hours

TBM Tunneling – Compressed Air Intervention at CP19

Value Engineering Phase Post Contract Award

• Special 4-weeks phase to evaluate specifications • Technical & contractual • Identify possibilities for optimization • Identify weak points in contract • Identify critical issues to pay attention for

SFRC Pre-Cast Segmental Lining

Segmental Lining Design – Double tapered Universalring (7 plus 1)

Keystone

Counterstone

Longitudinal Joint

Circumferential Joint (Smooth/Hardboards and plastic dowels) Use of EPDM Gasket with additional blackswell

Segmental Lining Production in Ireland

Segment Tracking

C310 - Thames Tunnel

X1-C-4-130912

Pre-Cast Segmental Lining Concrete Mix design, large scale fire tests at MFPA Leipzig

PP-fibre 0.75 kg/m3 PP-fibre 1.5 kg/m3

Successful fire test with 1.5kg HPR (high performance) Baumhüter PP-fibres

start ca. 1 year in advance to segment production (!!)

Innovation – TBM Launching with Movable Rig “Flying Launching System”

TBM Launching – “Flying Start”

Movable Rig System for a TBM Launch (HOCHTIEF Patent Solution)

• Easy, quick & safe Launching Operation; • No temp. rings or other means; • Improved Health & Safety; • Less space required.

Alternative Cross Passage Construction – SCL

• Alternative to Clients proposal with cast-iron rings • High demanding geology with water bearing fissures • Low overburden, i.e. CP19 • Constraints from available working space

additional steel- ring-support with emergency floodgate

Cross Passage Construction – SCL

Segment Removal • Coring & Cutting in Segment Joints • Removing Key Stone • Removal of Segmental 2K-Grout

Cross Passage Construction – SCL

Top Heading Excavation

Bench Excavation

Cross Passage Construction – SCL Shotcrete Application

Waterproofing Membrane

Cross Passage Construction – SCL Cross Passage completed

Secondary Lining – Central Section completed

Monitoring Tilt Meter Advanced Tunnel Drive Steering (ATDS) Real-Time Monitoring System . All appropriate structures within our works corridor are manually and/or automatically monitored . Shape accelerator arrays, hydrostatic levelling cells and tilt meters are installed on all sensitive structures . Piezometer for ground water levels . All monitoring date is shown real time in one system (ATDS) . Confidence to all stakeholders enabling consents & permissions being granted to pass under/over sensitive structures . Full control of source data and its management on site . Compliance with best practice in tunnelling and project insurance requirements Cathedral Hydrostatic Levelling Cell Sub Station

White Hart Screenshot ATDS Road Bridge

Conclusions

• Optimized Contractors Involvement (OCI) drives and Deep Excavation motivates innovations as well as people;

• Third Party interface management requires early involvement and detail knowledge of construction

techniques; Mix Shield

• Deep excavation next to Operating Railway line is feasible but requires robust control measures;

• Application of Mix-Shield was the right choice for C310. STP with Filter presses

• SCL-lining is feasible solution for temporary lining in Chalk for Cross Passages.

SCL in Chalk

Summary

A technically challenging project like C310 with many interfaces and challenges can be delivered to the original completion date.

Effective collaboration between the PM, Designer and Contractor’s technical and operational teams is delivering improved quality.

Evolution of TBM Tunneling under Thames since 1825

Tunneling Short Course 2016, 09/15/2016, Boulder, CO | Dr. Taner AYDOGMUS One Team, One Spirit 41 Crossrail C310 Thames Tunnel

Thank you for your Attention!

“If I could start again, I would build it better”

Marc Brunel (1769 – 1849)

Tunneling Short Course 2016, 09/15/2016, Boulder, CO | Dr. Taner AYDOGMUS One Team, One Spirit 42