3-D STABILITY ANALYSIS OF ABUTMENT SLOPES OF SRINAGAR DAM

Abstract

A 90 m high concrete gravity dam has been proposed across the river Alaknanda at Srinagar in District Tehri/Pauri Garhwal of Uttar Pradesh. The proposed dam axis is aligned in N 31°-14'-26" E or S 31°-14'-26" W direction in narrow gourge of river having a cord-height ratio of 3.52. Geotechnical investigations revealed that the proposed dam is located within a complexly folded, sheared and fractured sequence of quartzite and metabasic rocks. The foUndation rock of the proposed dam is quartzite and the metabasic rock is exposed in at higher levels on both the abutments. Study of rock slopes has been carried out in both the static and dynamic conditions In order to assess the stability of abutment slopes. Study shows that the overall slope of left abutment is stable while the overall slope of right abutment is unstable in both normal and dynamic conditions. Provision of cable anchors has been suggested to increase factor of safety to 1.5 in static condition and 1.0 in dynamic condition. The required capacity of anchors for unstable wedges has been worked out. C i