Iain Simmons - Well Connected Alliance - Waterview Tunnel construction update

Iain Simmons Well-Connected Alliance

(McConnell Dowell Constructors)

The Waterview Connection Project k

Progress update on the TBM Turnaround and Cross Passages

Australian Tunnelling Conference 14 October 2015

Introduction to the Project

Auckland New Zealand’s largest city- Population of 1.46 Mio

- One third of NZ’s population

- 36% of gross domestic product

- Less than 2km wide isthmus

Key transport links- Running through congested central corridor

- Overly dependent on central, single north-south spine

2009 Government Policy- Seven roads of national significance (RONS)

- Waterview Connection is the ‘jewel in the crown’

Western Ring Route- Missing link between SH 20 and SH 16

- 48km motorway ring route

- Links major population and industrial centres

Waterview Connection- 5km of new motorway

- 2.4km of which comprises two three lane tunnels

Project Costs- NZ $1.4 B

- Southern Zone – surface works from the tunnel’s southern portal to SH 20

- Tunnel Zone – underground works to build the twin 2.4 km three lane tunnels

- Northern Zone – surface works from the tunnel’s northern portals to SH 16, incl. GNR

interchange

3 Distinct Construction Zones

Tunnel Facts

- SB length 2398m, NB length 2410m

- Excavation dia. 14.41m, internal dia. 13.1m

- Max. vertical grade 5%, min. radius 1,500m

- Min. overburden above crown 10m at portals, max. overburden 40m

- 450mm segmental lining thickness

- Cross-passages 4.2m width x 4.8m wide x 11m long16 within driven tunnels, 2 within ventilation buildings

- One combined cross-passage / low point sump

- Cross-passage spacing 150m, length around 11m each

- 3 traffic lanes each direction

Tunnel Section – Connecting State Highway 16 with State Highway 20

Tunnel Work - Logistics

• All Logistics from Southern Portal

• 24hour Operation 6 days per Week

• Expected Spoil Volume approx. 800,000m3

• Spoil Removal via Conveyor Belt, up to 4620m3/day at peak progress

• 50,000 Truck Movements based on HPMV Trucks (17m3, 52 ton)

Multiservice Vehicle to carry one complete Segment Ring (9+1)

Multiservice Vehicle to carry two Invert Culverts

Geological Long Section

Three main Rock Types:

• Extremely weak locked Sands (EU1)

• Un-weathered Siltstone (EUL), alternating Siltstone/Sandstone (EUSL) and weak to very weak moderately cemented Sandstone (EUS2)

• Well cemented Sandstone (EUS3), volcaniclasticGrit/Sandstone (EUg)

Unit Unit Description Typical Strength

Vb Basalt UCS : 50 - 150 MPa

A Tauranga Group Alluvium Su : 30 – 70 kPa

ER Residual Soils Su: 50 – 150 kPa

EW Weathered ECBF Rock Su : 100 – 250 kPa

EU1 Extremely Weak Uncemented Sandstone

UCS : 0.5 - 2 MPa

EU2 Very Weak InterbeddedSandstone/Siltstone

UCS : 2 - 10 MPa

EU3 Weak Volcaniclastic, Coarse Grained Sandstone (Parnell Grit )

UCS : 10 – 30 MPa

TBM Face Pressure Utilisation

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Predicted face pressureOptional face pressure (+GW)Proposed face pressure by TRMActual face pressure applied

Chainage

Northern Portal TBM Operations

Northern Portal TBM Operations Face Pressure

Thrust Force

North Portal TBM Reception MethodologySectional view of TBM and support frame in northern sump

North Portal TBM Reception MethodologySectional view of TBM and support frame in northern sump

North Portal TBM Reception MethodologyReview of the requirement for the arrival frame for southern reception

TBM Head Inspection Cutterhead Condition at Breakthrough

Key facts

- Headwall support steel structure to secure headwallagainst TBM pressure before breakthrough

- TBM moved onto transport cradle for rotation and sideways movement

- Hydraulic jacks used to pull the cradle with the TBM loaded

- Steel floor plates and grease injection enable cradle to slide

- TBM startup using shove frame and temporary steel segments.

- Turnaround commenced in October 2014 and was completed 24 April 2015

including the construction of 250m of the northbound tunnel.

TBM turnaround - within NAT

TBM Turnaround Pulling System

TBM TurnaroundHydraulic Pulling Unit

Nicole sort out film clip

TBM Turnaround Back Up Gantry Pulling System

TBM Turnaround Back Up Gantry Pulling System

Cross Passages

• 16 number cross passages constructed between the main tunnels

• Each opening uses 6 steel segments

• Main tunnel lining propped before opening

• Horizontal and vertical wedges to ease removal of temporary panels

• Rigid connections with precast segments

• Special precast segments adjacent to the steel segments

Canopy Tubes

Cross Passages

Installing Props

Cross Passages

Cross PassagesPrimary Lining SprayedConcrete Support

Cross PassagesWaterproof MembranePermanent Lining Invert

Cross PassagesPermanent Lining Arch forms

Cross PassagesPermanent Lining Collars

Cross PassagesGround Improvement Pre-excavation Grouting at XP8, XP11 and XP12

Thank You