dave thomas - public transport authority - perth - forrestfield-airport link (fal) project, wa
TRANSCRIPT
Forrestfield-Airport LinkConnect. Fly. Grow
• 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