RESERVOIR SLOPE STABILITY OF BUNAKHA HYDRAULIC PROJECT BY FINITE ELEMENT METHOD

Abstract

The stability of the hill slopes along the reservoir rim is important for the feasibility of the hydroelectric
project. In this paper stability analysis of hill slopes of Bunakha Hydroelectric Project (BHEP), Bhutan has been carried
out in two different methods like three-dimensional (3-D) strength reduction method (SRM) and nonlinear static method.
Factor of safety (FOS) is determined for different conditions of dam like dry, steady seepage, submergence, drawdown
and earthquake loading at two critical slope chainages of 1700 and 4000m.The factor of safety is found to be 1.67 for
dry condition which increases to 1.97 in submergence condition at water level 110m at chainage 1700m. The rapid
drawdown condition of the slope is also studied when water level reduces from RL 2006 to 1956m and the FOS value of
slope is found to be 1.52. Similarly for another critical cross section at chainage 4000 m the reservoir slopes are found
to be safe.