Effect of material uncertainty on stochastic response of dams

Abstract

The present research considers the effect of uncertain material parameters on the stochastic dynamic response of an asphaltic lining dam–foundation system subjected to both stationary and non-stationary random excitation. The uncertain material parameters of interest are the shear modulus and mass density, which are modelled using a log-normal distribution. The Monte Carlo simulation method determines the stochastic seismic response of the dam–foundation system to spatially varying ground motion with uncertain material parameters. Consideration of the spatial variability of ground motion incorporates incoherence and wave passage effects from both stationary and non-stationary random excitations. A Heaviside modulating function is used throughout the study for the non-stationary responses. The results obtained indicate that variability of the shear modulus should be included in a stochastic dynamic analysis of an asphaltic lining dam–foundation system, but variability of the mass density can be neglected. Also, from the results, stationarity is a reasonable assumption for asphaltic lining dams in response to typical durations of strong shaking.