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Metro Tunnel

Western tunnel entrance construction plans

Building the western tunnel entrance

Building the western tunnel entrance will involve construction works on Childers Street to build a retaining wall that will support the embankment on the northern side of the rail corridor (east of Kensington Road), which is to be widened to accommodate the new Metro Tunnel tracks.

A decline structure will be built so trains can enter the new Metro Tunnel.

The tunnel entrance structure is proposed to be built via a 'cut and cover' method, which will see them excavated from the top down and the surface then reinstated over the top of the tunnels.

A construction support site on Hobsons Road and a tunnel boring machine (TBM) retrieval box will also be built to support tunnelling works.

It is not proposed that any construction activities for the Metro Tunnel Project will be undertaken in JJ Holland Park, other than potential upgrades to the shared use path.

Construction Snapshot

Construction works are continuing within the Kensington precinct during November and will include:

  • Site preparation and establishment activities on Childers Street and at the corner of Hobsons and Kensington roads
  • Service and site investigations on Childers Street (alongside and within the rail corridor)
  • Cycling detour route modifications at the Altona Street truncation
  • Tunnel cross passage ground improvement works on Lloyd Street
  • Installation of monitoring instrumentation in the rail corridor and surrounding areas
  • Bored piling adjacent to the rail line near South Kensington station.

Current Works

Bored piling works

Childers Street - Monday 12 to Wednesday 14 November

Removing the top layer of concrete from the bored piles adjacent to the rail corridor to complete stage one of piling works for the tunnel boring machine retrieval shaft.

This includes:

  • Using jackhammers to break back the top of the pile
  • High levels of noise during pile break back activities
  • If these dates change, directly impacted residents will receive additional notification.

Site preparation and establishment

Childers Street - Ongoing until early 2019

Site establishment and preparation activities ahead of major construction.

This includes:

  • Installation of temporary site fencing
  • Removal of the callistemon hedge to facilitate construction of the western tunnel entrance
  • All areas will be inspected for the presence of wildlife prior to any works
  • Low to medium levels of noise

Hobsons Road - Ongoing until early 2019

This includes:

  • Installation of temporary site fencing, hoarding, site offices and worker amenities
  • Site clearing activities
  • Low to medium levels of noise

Car park construction

Hobsons Road - Wednesday 14 November to late 2018

Construction of a long term, temporary off-set car park ahead of the closure of public parking on Childers Street.

This includes:

  • Excavation of materials
  • Rolling and grading the excavated surface to prepare for new asphalt pavement materials
  • Delivery of crushed rock, drainage pipes and light poles
  • Removal of soil and concrete materials
  • A water cart on site to mitigate dust
  • Low to medium levels of noise

Gas main protection works

Childers Street - Monday 12 to Friday 30 November

Works to protect the gas main beneath Childers Street.
This includes:

  • Non-destructive digging (NDD) to confirm the location of services
  • Excavation of road surface, inspection and recoating of the gas main, installation of monitoring equipment and reinstatement of the road surface
  • The detour of Childers Street and Tennyson Street (south of the truncation) residents and over-height vehicles accessing the Lloyd Street Business Estate via Kensington Road and Derby and Tennyson streets. Childers Street will be re-opened outside of work hours where possible
  • Periods of loud noise may be associated with NDD works. Other activities are expected to generate medium levels of noise.

Out of hours works

Works in the rail corridor are required to prepare for building the western tunnel entrance. To ensure the safety of rail users and
our workers, these activities can only be performed safely when trains are not operating.

Rail corridor between Lloyd Street and South Kensington station (night works) - 1am to 4am, Monday 26 to Thursday 29 November

Rail corridor monitoring instrumentation installation.

This includes:

  • Using a crane to lift a concrete block into place at the Lloyd Street bridge, within the cross passage ground improvement work area. The block will have a pole and monitoring station mounted to it
  • Workers using headlamps and hand equipment to install monitoring equipment within the rail corridor
  • Low levels of noise
  • Workers accessing the rail corridor from South Kensington station
  • No impact to any train services.

Rail corridor adjacent to Childers Street (24 hour works) - 11pm Saturday 3 to 7am Monday 5 November

Site preparation and investigation activities within the rail corridor.

This includes:

  • Works involving a small excavator
  • Installation of a delineation fence around the work site
  • Overhead wiring works involving an excavator
  • NDD and geotechnical drilling
  • Use of a temporary light tower within the rail corridor adjacent to Childers Street
  • Low to medium levels of noise
  • To minimise disruption to the local community and rail users, important Metro Trains Melbourne maintenance works will also be carried out at this time.

Tunnel cross passage ground improvement works

Lloyd Street - Ongoing until late 2018

Ground improvements works to strengthen the ground ahead of cross passage construction.

This includes:

  • NDD to locate and protect services
  • Injecting grout from the surface into the ground below Lloyd Street
  • 24/7 works to minimise traffic impacts on Lloyd Street as much as possible
  • Intermittent periods of medium to high level noise.

Site and service investigations

Childers Street (alongside and within rail corridor) - Ongoing until late 2018

Works to identify and confirm the location of existing underground services and help inform detailed planning for construction of the western tunnel entrance.

This includes:

  • NDD and geotechnical drilling, cone penetration and groundwater testing
  • Medium to high level noise during NDD
  • Geotechnical testing (bore hole) involving a drill rig to investigate the ground conditions.

Asbestos removal

Asbestos has been found on the Hobsons Road site previously and we anticipate more asbestos may be found during these works. The site will be monitored during works, and any asbestos found will be removed by independent occupational hygienists, in accordance with WorkSafe Victoria’s Compliance Code 2008 for Removing Asbestos in Workplaces. Removal of asbestos-containing material by licensed removalists does not post any safety risk to site staff or the public.

Piling works

Piling will be undertaken in two stages from mid-September and the end of 2018 to construct the walls of the TBM retrieval shaft.

The first stage will commence in mid-September, adjacent to the rail lines on the southern side of Childers Street. This will include:

  • Constructing a pile guide wall
  • Using piling rigs to drill holes approximately 22 metres deep
  • Lifting steel cages into the drilled hole
  • Pouring concrete into the hole to create the pile
  • Breaking back the top of the pile once the concrete is set using jackhammers
  • Constructing a concrete pile beam that links the installed piles
  • Up to 50 truck movements per day to support piling activities.

In total, approximately 110 piles will be installed within the Childers Street worksite.

These works may generate intermittent periods of low to medium level noise and vibration. These works will be undertaken during normal construction hours only.

Detour route modifications

While Childers Street is closed to through traffic, cyclists will be detoured through Altona Street.

There will also be limited periods during construction where it is not possible for over-height vehicles to access the Lloyd Street Business Estate through the Childers Street worksite. During these limited periods, a detour via Derby and Tennyson Streets will be used, with reduced speed limits and traffic controllers in place.

Works are required to prepare these detour routes for use, see details below the map.

Map showing the work sites for detour route modifications in Kensington. These works are described below.

Kensington Road

At Kensington Road, we need to remove the traffic islands on either side of the Derby Street intersection, reseal the roads and install new line marking.

What to be aware of

  • There will be periods of loud noise associated with road cutting and asphalting works.
  • The speed limit will be lowered to 40 km/h between Cairncross Lane and Epsom Road.
  • Eight on-street parking spaces on Kensington Road will be occupied during works.
  • Traffic flow will be maintained in both directions via a shuttle flow arrangement.

Altona Street

To provide a detour for cyclists, we need to widen the footpath at the Altona Street truncation to create a shared-use path.

What to be aware of

  • Non-destructive digging (NDD) will be undertaken to locate and protect tree roots prior to works commencing.
  • The path will be widened and small ramps installed to connect the road to the shared-use path.
  • The new path will be line marked.
  • There is expected to be periods of loud noise associated with non-destructive digging and path installation.
  • Car parking on Altona Street will not be impacted by these works.
  • Restricted access to vehicles through the modified truncation will be maintained.
  • Please obey signage and traffic controllers during these works.

Tennyson Street

At Tennyson Street, we need to level the surface of the road at the existing truncation and install movable barriers to ensure the road remains closed when the over-height vehicle detour is not in use.

What to be aware of

  • The road will be resealed and new line marking installed.
  • There is expected to be periods of loud noise associated with road levelling and asphalting activities.
  • Up to six on-street parking spaces on Tennyson Street will be occupied during these works.
  • Temporary narrowing of the cycling lanes either side of the existing truncation during works will be required. Cyclists are advised to obey signage and traffic controllers in the area.
  • Some trimming of branches that overhang the road may be required. No trees will be removed along Tennyson Street.

Derby Street

Some tree trimming may be required along Derby Street to facilitate the safe detouring of over-height vehicles accessing the Lloyd Street Business Estate. These clearances have been recently surveyed and this information is currently being assessed by our traffic and environmental teams.

Ormond Street

To enable construction of the temporary roundabout, the truncation at the southern end of Ormond Street will be moved approximately ten metres north of its current location.

This is to ensure Ormond Street remains closed at Childers Street during construction.

What to be aware of

  • Kerbing will be installed to create the new section of truncation
  • There is expected to be periods of loud noise associated with road cutting and asphalting activities
  • Footpaths will be realigned to cross over the modified truncation
  • Part of the southern section of the existing truncation will be removed as part of temporary roundabout construction
  • Three on-street parking spaces may be impacted during these works
  • Two parking spaces will be removed as part of this modification.

Project delivery

Given the scale and complexity of the project, works to build the Metro Tunnel Project will be delivered via a series of packages. Each package of works will focus on different elements of the Metro Tunnel.

The exact design of the western tunnel entrance may continue to evolve as we work with potential contractors ahead of contract award. Major works to build the western tunnel entrance will commence in 2018. It is estimated that construction of the western tunnel entrance will take around three years.

After the main civil works are complete, the entrance is anticipated to be used by contractors to fit out the tunnel for approximately another two years.

Key construction activities

Key construction activities to build the western tunnel entrance will include:

  • Preparatory works including the protection and removal of a limited number of trees on Childers Street, and relocation of utilities including the electrical high voltage transmission towers.
  • Demolition of one residential property.
  • Temporary relocation of public car parking and the shared pedestrian and cyclist path on Childers Street
  • Construction of the TBM retrieval shaft.
  • Widening of the rail reserve to accommodate additional tracks and install retaining walls alongside Childers Street.
  • Cut and cover excavation of the tunnel entrance structure.
  • Track works and the installation of signalling and communications systems.
  • Site reinstatement including upgrading the shared pedestrian and cyclist path, altered parking and road layout and landscaping.
  • Tunnel fit-out (installation of track, overhead line equipment and services).