Influence of soil spatial variability and stochastic Ground-Motion on the dynamic behavior of a slope

A probabilistic dynamic approach is used for the slope stability analysis. In this approach, the effect of both the soil spatial variability and the variability of the Ground-Motion (GM) time history on the dynamic responses (amplification, permanent displacement) are studied and discussed. The soil shear modulus G is considered as an isotropic non-Gaussian random field. The simulation of random acceleration time histories based on a real target accelerogram is done using a fully nonstationary stochastic model in both the time and the frequency domains. The deterministic model is based on numerical simulations. 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 the shear modulus leads to a small variability of the dynamic responses; (ii) 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.