Seismic Analysis of Terbala Dam

Abstract

Tarbela Dam, which is the back bone of Pakistan’s hydropower and water storage potential, is subjected to the problems of seismicity and sedimentation both in aggravated conditions. As four faults occur with in the radius of 30 km of the dam’s embankment. One of these faults has potential of producing earthquake of magnitude 8.0. The source of the Indus River is glacial melt water from the Himalayas ; the river carries huge amounts of sediment. The annual suspended sediment load is about 430 million tons per year. This means that, over time, the reservoir will fill. In 1982, TAMS performed the seismic analysis of the dam with Pacoima earthquake record. As the softwares were not much developed at that time and the seismic data was also not available so, they made several assumptions which make the results safer. They themselves conclude that there results which are based on several assumptions leads the results to be mores safer then reality. Moreover, they did not study the behavior of the dam during earthquake which is one of the most important aspect of dynamic analysis. Therefore, keeping in view the vitality of the dam it seems imperative to perform the dynamic analysis with actual earthquake record and to study the effects of sediments on dam stability