Plugging of diversion tunnel – An unique challenge

Diversion tunnel plugging is normally first major milestone for commissioning generation from a hydro power project and is normally associated with major problems and challenges. Plugging of diversion tunnel of Indira Sagar Project was no exception. Heavy leakages were observed when gates were lowered to start plugging. Problem added another diversion of complexity when steel liner along with second stage concrete got detached leaving the gates immobile. Taking up challenge, the highly motivated site team with full support from corporate management accomplished the task without affecting compressed commissioning schedule. The paper deals with the problems encountered during diversion tunnel plugging and methodology adopted to accomplish the task.