Critical Appraisal of Common Simplified Assumptions in Seismic Stability Analyses of Gravity Dams

Abstract

AbstractIn practical seismic stability analyses of gravity dams, it is common to (1) oversimplify irregular dam-rock interfaces, (2) neglect the effects of cohesion and tensile strength, and (3) ignore the effects of vertical ground accelerations. In this paper, a critical appraisal of such simplifying assumptions is proposed. For this purpose, an efficient procedure for dam seismic stability analysis not requiring the above-mentioned assumptions is first proposed. The developed technique is applied to investigate the seismic stability of an existing gravity dam with a stepped dam-rock foundation. The response of the dam is studied under the effects of two earthquakes differing by their frequency contents. The resulting stresses at the dam-rock interface, sliding safety factors, crack lengths, and residual displacements are examined. Detailed discussion of the effects of dam-rock geometry, mechanical properties at the dam-rock interface, and the vertical seismic component is presented. It is primarily sho...