Innovations in Tunnelling Technologies in Hydro Project

Dr. Rakesh Kumar Khali, Vice President - Operations, (Tunnel, UG Structures & Hydro Power), G.R. Infraprojects Ltd., describes the construction of the Tehri Pump Storage Project (4X250 MW) and the innovative technologies in Vertical Shafts and Tail Race Tunnels

This article discusses the innovations made in excavation and support of reverse slope for slanting portion of Upstream Surge Shaft - 3 & 4 and also analyses the innovative methods adopted for concrete lining of TRTs. It further describes the steps taken to ensure the stability and effective excavation of Tehri PSP U/s Surge-Shafts Slant-portion Design, and the measures taken to safeguard excavation and support, casting of collar beam and erection of truss girder for gantry movement. Here, the focus is on how the invert lining of TRT’s done first to be followed by an overt lining. The practice is very uncommon in India and sets up a successful example for other industry partners.