INFLUENCE OF CORE THICKNESS ON RESPONSE OF EARTH & ROCKFILL DAM DURING EARTHQUAKE

Abstract

Static as well dynamic response of Earth and Rockfill dams are influenced by the zoning and fill material characteristics apart from the topography of the site. Various researchers have studied the effect of the different components. The present work deals with the influence of core thickness on the static as well as dynamic response of earth and rockfill dam. For present study, five cases of earth and rockfill dam with central core have been considered. These cases are of core. thickness 0.2H, 0.6H, H, 1.4H and 2.H respectively with top width of 5 m in each case. Here H, height of dam, has been taken as 100m for all cases. In static analysis the effect of core thickness has been studied on both dry and full reservoir conditions. The stresses and displacements have been determined. For dynamic analysis IS : 1893-1984 code spectra has been used for seismic Input and a constant damping of 10% in all the modes is assumed. The dynamic displacements/stresses have been combined with static, displacements/stresses and mode shapes have been evolved. The acceleration variation along the height has also been determined. The results of static and dynamic analyses clearly indicate that dam with thicker core will prove to be superior to the dam with thinner core under normal and seismic conditions.