Forrestfield-Airport LinkConnect. Fly. Grow

Overview

• Planning for the project began in 2008

• 2013 State election brought the project forward

with the main objective to connect to the

eastern suburbs

• Infrastructure options were considered –

including an above ground and two below

ground options

Background

• Below ground was always needed to tunnel under Perth Airport and this provides the best economic and social option

• The chosen route provides the best solution to service the future Consolidated Airport precinct and the development potential of the surrounding areas

Stations

Features• Platform lengths to accommodate 6-car trains

• Anticipate island platforms at each station

• Integration concepts subject to consultation

• Anticipated that in 2021, over 2,000 people

per hour will use the three stations’ services

during peak hours.

Station comparisons• Airport West Station - shallow underground

station, bus interchange and parking for 500

cars (similar to Esplanade Station).

• Consolidated Airport Station - deeper

station, on Commonwealth land (similar to

Perth Underground Station).

• Forrestfield Station - at grade station with

railcar stowage, bus interchange and parking

for up to 2,500 cars (similar to Butler Station).

Route options

Project scope

Location and scope

• 7.3km twin bored tunnels through soft

ground conditions below groundwater

• Tunnelling beneath Swan River and

operating Perth Airport

• Bus / train interchanges at Airport West

and Forrestfield

• Tunnel cross passages and egress shafts

• Rail infrastructure and operating systems

Three new stations

• Airport West Station

• Consolidated Airport Station

• Forrestfield Station

Project benefits

• Quick and efficient connections (bus feeder and rail)

• Reduces car dependency and relieves traffic congestion

• Boosts employment, residential and economic growth

• Opens up the Eastern Suburbs to the suburban rail network

• Minimises the physical divide of the airport

• Improves social equity and quality of life for communities

Promotes new and existing development

areas surrounding Airport West and

Forrestfield Stations

Station proximity to Airport Terminals

provides direct access to Airport Central

precinct

Project timeline

PDP approval

August 2014

EOI called

January 2015

EOI closed

March 2015

RFP released

June 2015

Contract award

mid 2016

Tunnelling

commences

2017

Trains running

2020

Design and construction

• A Design and Construct contract – 4.5 years

• With some elements of maintenance (10 years)

• Rail systems commissioning – critical activities

• Excludes rollingstock (trains and buses)

Construction methodology

Station Boxes and Dive Structures

• Diaphragm walls

• Top down / bottom up construction

• Dewatering

Emergency Egress Shafts

• Diaphragm walls

• Dewatering

Bored Tunnelling

• Tunnel Boring Machines

• Pre-cast tunnel lining segments

Cross Passages

• Ground strengthening and sprayed concrete

lining

Scope of works and technical

criteria

EPB / Slurry machines

• Slurry mode only beneath Airport

Land

What are we mandating for the SWTC?

Dewatering limits during

construction

• 1.0m on dewatering

drawdown below seasonal

variations

Segmental lining

• double gasketted, rebar and

fibres ,external epoxy

coating, double convex

joints • Cross passages and egress

shaft spacing- bespoke

approach agreed with DFES

Ground freezing airside

• Lack of ground level access for

cross passages under airport

Proposed route

• The tunnel will extend under the Swan River, which will be a first for Perth

• This technique has been practiced globally with many cities around the

world having tunnels under bodies of water

• The construction and tunnel will have minimal impact on the environment

• The tunnels are located below a soft, mud-filled palaeochannel

Vertical alignment

• Similar in many respects to successful 2004-2007 Perth City Rail project

• Bassendean Sands (0.5m to 5m thick)

• Gnangara Sands (up to 5m thick)

• Guildford (Perth) Formation up to 20m thick (Alluvial silts, sands and

clays)

• Ascot Formation between 13 to 30 m depth, 3.0 m to 17 m thick

(variable sand to gravel)

• Osborne Formation bedrock at around 25m depth, 100m to 200m thick)

• Groundwater at 1.5m to 3m depth, in Bassendean Sand

• All soils in profile are ASS to varying degrees

• Suitable for cut-and-cover tunnels, deep excavations and bored tunnels

with appropriate risk management systems

Perth Airport ground conditions

* Indicative Airport design 2020

Alignment through airport

Tunnelling under airports

worldwide

Project

Name

Zürich

Kloten

Airport

London

Heathrow

Sydney

Airport

Minneapolis

St. Paul

International

Brussels

Diabolo

Dulles

International

(Washington DC)

Forrestfield-

Airport Link

Year

opened1980 1998 2000 2004 2012 2018 (expected)

2020

(expected)

TBM Type Slurry EPB Slurry EPB Slurry EPB Slurry/EPB

Excavated

Diameter6.3m 9.2m 10.7m 6.5m 8.3m 6.4m 6.7m

EPB – Earth Pressure Balance

Previous bored tunnelling in WA

Sewer project in

Subiaco

New MetroRail

Port Hedland

Conveyor TunnelAlkimos

wastewater

Perth Main Sewer. Section 3

– 1.4km of 2m diameter.

1.4km of twin bored rail

tunnels of 6.2m diameter

running directly under Perth

CBD.

1.3km conveyor tunnel of

5m diameter beneath Port

Hedland Harbour; capable of

carrying 10,000 tonnes of

ore per hour.

6.3km tunnel of 2m diameter

to a maximum depth of 20m.

Tunnel Boring Machines

Slurry MixshieldEarth Pressure Balance

• Forrestfield-Airport Link specified Earth Pressure Balance

(EPB) and Slurry Mixshield

• Likely to be built in China with key components, such as

bearings, manufactured in Europe or Japan

• 80-140m in length and weigh up to 1,000 tonnes

• Serviced by track or rubber tyre vehicles

• Sophisticated control systems

Control screens

Anticipated tunnel features

• Pre-cast tunnel lining segments 275mm thick (approximately)

• Steel bar and fibre reinforcement

• Ring width 1.6m

• Waterproofing

Cross passages and egress shafts

Cross passages

• Techniques

Jet grouting

Ground freezing – brine

• Typical spacing

>400m apart

Emergency Egress shafts

• Spaced every 780m

Stages of geotechnical

investigations

Phase Timing Details

1 For Project Definition Plan Desktop study and preliminary site

investigation by PTA

2 Prior to calling for Expressions of

Interest (EOI) responses

Detailed site investigation and interpretive

engineering studies by Golder Associates

3 During EOI stage Factual investigation studies proposed by EOI

applicants and commissioned by PTA

4 During the Request for Proposal (RFP)

design phase

Factual investigation studies proposed by

shortlisted respondents and commissioned by

PTA

5 During RFP evaluation Factual investigations in consultation with

preferred proponent (if required)

6 Following award of contract Scoped and commissioned by D&C contractor

Scope of geotechnical information

Phase 2 scope

• Over 400 boreholes, cone penetrometer tests and test pits at around 50m spacing (where possible),

including barge drilling in Swan River

• Spoil reuse study (anticipated 900,000+m³)

• Geophysics trial

• Pump testing, long term groundwater level monitoring in aquifers

• Laboratory testing including abrasion and frozen soil testing

• Collection of foundation information on existing facilities

• Geological and hydrogeological models of route

• Preliminary assessment of construction impacts on nearby facilities (e.g. deep foundation element

construction, aquifer drawdown and excavation)

• Ground gas monitoring

• Review of man-made obstructions to tunnelling

Complexities at airport

Runways and taxiways

Airport control tower

Security

Disruption to utilities

Construction impact on traffic

Key airport asset monitoring

Undertaken by PTA, to provide to Tenderers for assessment of ground

movement risk

• InSAR

• Tower monitoring

• Ground elevation survey of airside project corridor and runways:

- Terrestrial laser scanning of pavements in project corridor

- Traditional survey of grassed areas in project corridor

- Autorod and level profiling of both runways

• Runway ride quality performance assessment

Environmental studies

• Detailed Site Investigation - Acid Sulfate Soils and soil and groundwater quality

• Baseline environmental monitoring

• Private bore survey

• Heritage survey

Aboriginal engagement

Cultural heritage

monitoring

Employment targets

The Contractor will provide an Aboriginal Participation Plan

Business

opportunities

Reconciliation action

plan

Design integration

Much more than a ‘train to the airport’, the

project delivers many direct benefits

Land development at stations

Airport West

Station is the

central part of

the DA6 Vision

Plan for the City

of Belmont

Forrestfield

Station will

provide a hub for

the new District

Structure Plan

for the Shire of

Kalamunda

Mixed use land

developments,

higher density

living, business

opportunities

Next steps

RFP process continuing

Further noise and vibration modelling (in car noise)

Ongoing limited geotechnical investigations (in consultation with shortlisted respondents)

Contract award due mid-2016

Ongoing community engagement