EFFECTIVENESS OF UPSTREAM BLANKET AND GROUTING IN CONTROL OF SEEPAGE AT KHANPUR DAM PROJECT

Abstract

Khanpur Dam in Pakistan was constructed on deep alluvial deposits underlain by foundation rock. The dam, since its operation in 1983, has predicament of seepage and in spite of several studies and remedial measures taken in this regard, the problem has not been resolved completely. The present study presents a review of performance of different components of Khanpur Dam in the context of seepage. In this research, Geostudio 2004 package has been used to see the effect of different factors on the quantity of seepage and the results have been validated with the help of field data. The research work concludes that upstream blanket is working efficiently and seepage through the main dam has been stabilized due to the strengthening of the upstream blanket because of sediment deposition. Geostudio analysis as well as field data has indicated that previous grout work at left and right abutments has failed to produce the required results and seepage which is being measured at the downstream toe of the dam is through the abutments instead of through the body or foundations of the dam and recommends that by extending the grout curtain up to a depth of 140' in case of left abutment and to a depth of 160' in case of right abutment, the quantities of seepage can significantly be reduced.