A JV of Strabag and Indian firm Afcons has won a contract to build a road tunnel at Rohtang Pass in Himachal Pradesh state.
The Euro250M (US$370M) contract for the 8.8km long tunnel was awarded by a national agency, the Border Roads Organisation (BRO). Strabag’s affiliate Dywidag International is to undertake the tunnelling work.
The tunnel cross-section is designed to be horseshoe-shaped with a finished width of 10m, including 1m wide walkways at each side. Within the cross-section of the single bore and below the finished roadway, is to be a 2.25m high by 3.6m wide escape tunnel.
Drill and blast excavation of the tunnel is scheduled to start in the second quarter of 2010 and be completed by the end of 2015. Lining support is to be fibre-reinforced shotcrete and bolts with ribs in weakest zones.
Geology along the alignment comprises uniformally dipping alternate sequences of quartzites, quartzitic schists and thin bands of quart diolite schists. There are also three anticipated fault zones and expectation of squeezing ground.
While tunnelling work will proceed from both portals the majority will be done from the south due to accessibility problems caused by snow during winter at the north end.
Rohtang is one of the world’s highest mountain passes, and the tunnel is to be built at an elevation of 3,100m. The new tunnel will be a link that improves year-round use of the Leh-Manali highway.
