The Pir Panjal Railway Tunnel

The Pir Panjal Railway Tunnel was the first tunnel in India to be constructed in accordance with the principles of the New Austrian Tunnelling Method. Despite very heterogeneous rock conditions with frequent changes of solid and completely fractured rock, with high water inflow in places, the work progressed without prolonged excavation-related interruption and delays. This was possible because of the design and construction method, which permits prompt reaction to changing geology and installation of initial support measures, but also rapid adaptation of support measures to cope with the conditions of a young rock mass like the Himalayas. An important tool in regard to control and manage the ground deformations in the different geological conditions was the 3D monitoring of the lining displacements and its interpretation.
The tunnel was driven from numerous faces by conventional mined tunnelling methods using drill and blast as well as roadheader, with immediate installation of the primary support. The excavation and lining works were completed in late 2012, mechanical and electrical works in early 2013. Considering the difficult geology, extreme weather situation in winter and the hostile conditions of the area, the overall performance was satisfactory, although the initially scheduled target was not achieved. The tunnel has now been in operation since summer 2013.