Influence of soil spatial variability and stochastic ground-motion on the dynamic behaviour of a slope
Abstract
A probabilistic dynamic approach is used for the slope stability analysis. In this approach, the effect of both the soil spatial and the Ground-Motion (GM) time variabilities on the dynamic responses are studied and discussed. The soil shear modulus G is considered as an isotropic non-Gaussian random field. The simulation of variable acceleration time histories based on a real target accelerogram is done using a fully nonstationary stochastic model (i.e. which has nonstationary characteristics in both time and frequency domains). The deterministic model is based on numerical simulations using the dynamic option of the finite difference code FLAC3D. An efficient uncertainty propagation methodology which builds up a sparse polynomial chaos expansion for the dynamic responses is used. The probabilistic numerical results have shown that: (i) the decrease in the autocorrelation distance of G (i.e. the soil heterogeneity) leads to a small variability of the dynamic responses; (ii) adding the randomness of the earthquake GM has a significant influence on the variability of the dynamic responses; (iii) the probabilistic mean values of the dynamic responses are more critical than the deterministic ones.
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