Tunnels will provide an underground bypass of Yarraville, helping to reduce truck traffic on local roads and improve safety and amenity above ground, while providing a direct and efficient road connection below ground.
There are many important factors that must be considered in designing the tunnels, including:
- appearance and visual amenity
- connectivity and accessibility
- disposal/usage of spoil
- environmental changes or impacts
- existing and future traffic flows and volumes
- expected ground and groundwater conditions
- future operations and maintenance
- land use at tunnel portals
- stakeholder requirements and needs
- underground services (e.g. sewerage, water pipes, gas and electricity)
- value for money
- vertical and horizontal alignment for constructability constraints and operation.
With thousands of tunnels operating around the world, we know that tunnels can be built safely and without affecting homes above ground.
Transurban is experienced in the building and operation of road tunnels – with CityLink in Melbourne and others in Sydney and Brisbane.
Tunnel Boring Machines (TBMs) would most likely be used to construct the Western Distributor tunnels. TBMs are custom-built for specific projects to suit the local ground conditions. They excavate and line the tunnels while removing material from the tunnelling area.
With more and more major construction now happening in urban areas, construction companies are finding new and innovative ways to reduce construction impacts; however some disturbance to the surrounding communities is to be expected during construction of any major project.
Noise and vibration are carefully managed and are monitored throughout construction. Depending on the ground conditions and depth of the tunnel, some residents close to the tunnel route may experience some temporary vibration and/or regenerated noise as the TBM progresses through their area.
Safety and fit out
Tunnels are designed for safety and must meet strict national and international safety regulations.
The diagram below shows the typical features of a tunnel:
- 24-hour surveillance
- Fire suppression systems
- Ventilation systems
- Emergency management equipment
- Safe refuge areas
- Cross passages for connecting the tunnels.
Benefits of using a tunnel
While tunnels are complex and expensive to build and maintain, there are many potential benefits, including:
- reduced need for surface land acquisition
- moves through traffic away from homes
- provides a high quality motorway connection under built-up areas
- reduces traffic noise on local streets
- provides the opportunity to improve local air quality by reducing truck volumes on local streets
- reduces disruption during construction
- creates urban redevelopment opportunities
- reduces traffic load on the general road network
- improves transport efficiency by,bypassing hotspots.
Environmental Effects Statement
The Environment Effects Statement (EES)being prepared for the project will identify and assess potential construction techniques and impacts.
Some of the impacts or topics the EES will cover regarding construction include noise, dust, vibration, water disposal, spoil management and haulage routes, contaminated sites, ground movement, traffic, access and site compounds and contractor parking.
Through specialist studies which inform the impact assessments and the outcomes of the EES, detailed information will enable comprehensive management plans to be developed and implemented.
Initial site investigations have helped us to better understand local ground conditions and support the development of the Western Distributor.