Seismic analysis of concrete gravity dam under seepage load

Abstract

The concrete dams may be exposed to earthquakes that lead to their collapse caused loss of quantities of water, lives, and substantial financial. The behavior of dams under the influence of such loads is very important to know the safety requirements. One of the main factors affecting the behavior of concrete dam during an earthquake is the interaction between the reservoir-dam-foundation. This research presents a parametric study of the effect of foundation stiffness, seismic frequency, and water level on the dynamic response of the dam taking into account the problem of reservoir-dam-foundation interaction. When studying the effect of frequency, the dam was exposed to three earthquakes with different frequencies but with the same acceleration. The results of the analysis of the effect foundation stiffness were obtained by suggesting different values of the modules of elasticity for soil.  A 2-D FEM  was used to model the Dam using  ANSYS software. The results show that the Ground motion variation affects dam seismic response, although the different ground motions have the same peak acceleration.  In all cases of the water height, there are tensile stresses at the heel which led to a crack between the dam body at the heel and the rock foundation. When the stiffness increases, the deformation decreases which occurs due to the decrease in the settlement of the foundation. The importance of extending the rock investigation studies in both the upstream and downstream directions if the dam has to be constructed over a low stiffness foundation. Results confirm the dominant effect of foundation stiffness on dam response over other parameters.