ANALYSIS OF GROUT CURTAIN EFFICIENCY IN EARTH AND ROCKFILL DAMS A CASE STUDY OF BILI-BILI DAM - I N INDONESIA

Abstract

In majority of the dams, a single-line curtain has been in use for a long time to reduce the uplift pressure and seepage on downstream side. The decision whether or not it is to grout the foundation of the dams requires considerable judgement and experience, and a close coordination with engineering geologist. By providing a fully effective grout curtain, hydrostatic pressure will -be reduced up to a certain magnitude, this is due to the length of the seepage path travelled through the foundation. Effectiveness of a grout curtain depends on its depth and thickness. Studies of a number of dams by Cassagrande, theoretical analysis of thin cut-offs by Ambraseys and Cedergren has shown that a single-line grouting is not effective in reducing hydrostatic pressures. With a view to see the effectiveness of grout curtain, data has been collected for 32 dams and analysed to develop guidelines for design parameters. Bili-Bili Dam in Indonesia has been studied in detail to check the application of the guidelines.