Green Tunnels

When a new transportation route either road or rail is planned across an environmentally sensitive area "Green Tunnels" can mitigate many of the local concerns. "Green Tunnels" or "Tunnels in Trenches" are built in a deep cutting and covered with a "roof" which is planted with grass to disguise the line and make it blend in with the environment. It can help maintain local access, minimise noise, visual impact and environmental damage.

We have developed a new approach (patent applied for) based on the "Jacked Deck" for constructing "Green Tunnels" which provides considerable benefits compared to traditional approaches.

  • Activities are centered on one location with drive lengths of 1000m or more. With drives in opposite directions 2000m or more can be installed from a single launch area.
  • We can switch from open cut to tunnel mode, with minimal operational changes, under roads and where overburden cover is greater.
  • Minimal land take is required as working is confined to the tunnel width plus a small margin. No temporary haul roads along the tunnel route are required
  • Locations for launch areas can be chosen for access, storage, working and minimal environmental impact
  • Large percentage of construction undertaken underground without environmental disturbance
  • Greatly reduces environmental impact and rapid installation allows for shorter occupation and construction times.

The Jacked Deck methodology includes


Installing the launch pit and storage area

Driving twin access tunnels of around 3m diameter



Installing piles from the access tunnel to form side walls of structures using low head room piling equipment




Installing capping beams and slide paths within the tunnels




For shallow locations the installed units form the haul route for transporting spoil back to the launch pit. Spoil excavated from within the shield can be transported back through the formed tunnel.

For deeper locations, when excavation from the surface is not required and the Jacked Deck is tunnelled forward the spoil excavated from within the shield can be transported back through the formed tunnel.

As deck units are advanced sections of the access tunnels are removed to expose the slide path

Once the tunnel installation is complete backfilling over the deck can be undertaken

Final excavation and finishing to piled walls and installation of a floor slab, if required, can all be carried out whilst deck jacking is underway.