Trenchless works ramp up in eastern states

The last three months have seen an increased level of activity in Tunnelcorp’s operations, with multiple sites often operating seven days per week to keep up with tight programs.

Slurry microtunnelling

Tunnelcorp is currently operating its MTS slurry microtunnelling machine on two drives for a gas pipeline at Roma, Queensland.

DN900 concrete jacking pipes were installed under the Iona-Bradlomey highway for a length of 53 m and the Warrego highway/QR rail line bore was 83 m in length.

The encasing pipe will house a gas pipeline installed on centralising spiders and the annulus grouted.

The client required a high degree of accuracy due to multiple optic fibre cable crossings in the path of the longer bore.

In addition, Tunnelcorp recently purchased a MTS2000 slurry microtunneller with a full slurry recycling system.

The unit is currently set up to install pipes from DN800 to DN1500 with a capacity to increase size to DN2000.

The machine is computer-operated and has two complete front-end drilling units for 800 mm and 1,200 mm with up-skin kits for 900, 1,000 and 1,500 mm ID pipes.

Soft ground, mixed ground and hard rock heads for all sizes complete the package.

Pipe jacking

Two new DN2700 concrete pipelines are currently being jacked over 1,800 mm of damaged corrugated steel stormwater pipes on sites 20 km apart near Gin Gin, Queensland.

A steerable steel shield envelopes the 1,800 pipe before the damaged sections are removed thus ensuring face stability under the road.

During construction using an 800 tonne (t) jacking system, the pipelines are being regraded to a more acceptable level to ensure longevity of the new pipeline and the areas of scour protection.

Tunnelcorp has just completed a 42 m, DN1500 mm pipe jack under a raised road in Bellingen, New South Wales, to replace a damaged DN750 concrete stormwater culvert.

The bore exited 8 mm off grade and was completed ahead of program.

The 750 mm pipe was sliplined with a 600 mm high-density polyethylene pipe to add capacity to the crossing and the annulus grouted. New concrete headwalls completed the project.

A 300 t jacking rig has been mobilised to complete two DN1200 RC pipe crossings of the M1 freeway at Somersby, NSW.

The open-faced jacking rig is expected to encounter fill material comprising crushed rock with boulders up to 300 mm in diameter.

The two bores are 41 m and 75 m in length.

Tunnelcorp’s scope includes construction of the working slabs and thrust walls.

Tunnelcorp is a multi-disciplinary trenchless technology contractor operating throughout both Australia and New Zealand, providing slurry and vacuum microtunnelling, pipe jacking, box culvert jacking, auger boring and canopy support pipe structure services.

It is a specialist trenchless contractor able to complete sometimes difficult crossings on time and within budget.

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