Volume 14, No. 1, 2020
Received: 2020/03/16, Accepted:
Authors:
Vishal Deoda; Shrabony Adhikary; Srinivasa Raju V;
Abstract:
The present work attempts to study the seismic behaviour of two earthen dams, viz. Chang and Kaswati dam, located in Gujarat, India for different sets of time histories. Each set comprises eight earthquake time histories, where one time history set is compatible to Indian Standard IS-1893(1)-2016, Type –II spectrum (SC) and
another time history set is compatible to Conditional Mean Spectrum (CMS) as per the recent state-of-art related to selection of time histories for dynamic analysis. Numerical simulation has been carried out in Geo studio (2012) software which uses the finite element method for analyzing the earthen dams and includes SEEP/W, SLOPE/W and QUAKE/W analysis for estimating seepage, slope stability and dynamic response, respectively. Steady-state method is used to determine the seepage through the dam body in seepage analysis and Morgenstern-Price method is used to determine the factor of safety in stability analysis. The failure phenomenon in the earthen dam after the application of earthquake load is studied, in which the dam material
follows Mohr-Coulomb failure criterion. The reservoir level has been considered as one of the parameters for the numerical study. It is observed that the water level in the upstream has a significant effect on relative horizontal displacement as well as relative vertical displacement of the dam crest, amplification of ground motion at the dam crest and post-factor of safety of the dam for the considered sets of earthquake time histories. Moreover, it is also concluded that the selection of time histories is a very important step for seismic analysis of dams.
Keywords:
Earthen dam, Conditional mean spectrum, Spectrum compatible time histories, Soil amplification