ANALYSIS OF VERTICAL SURGE SHAFTS EXCAVATED IN JOINTED ROCKS

Abstract

Shafts play an essential part in the construction, operation and maintenance of tunnels and deep underground structures. Excavation, analysis, design of underground openings have been difficult and there has been no particular defined method for different rock mass conditions encountered during excavation. The problem considered in this dissertation work is the analysis of Surge tank in Chhibro underground powerhouse area. Surge tank was provided to carry water from Ichari dam reservoir, at the end of long headrace tunnel on the upstream of powerhouse. 1 OOm high and 20m diameter underground surge tank is located in limestone and slates. 2-D elasto-plastic stress strain analysis for different stages of excavation sequence of a surge tank.