Stochastic stability analysis of geosynthetic reinforced slopes subjected to harmonic base shaking

Geosynthetic reinforcement is a lucrative solution for stabilizing the recurring failure of slopes. This paper presents an efficient probabilistic approach to analyze the internal stability of geosynthetic reinforced slopes (GRSs) resting on a soil deposit subjected to harmonic base shaking. Collocation based Stochastic Response Surface (SRS) method is used for the same. The deterministic analysis is performed employing a rigorous formulation of Horizontal Slice Method (HSM) in a modified pseudo-dynamic framework. The formulation satisfies the horizontal, vertical, and the moment equilibrium equations of each slice. The algorithm is made efficient using the non-linear constrained optimization. The effect of exciting frequency of soil on the stability of GRS is examined in detail. The accuracy of the proposed probabilistic formulation is also compared with the results of the FORM. Four input parameters are considered to be random in nature namely internal soil friction angle, unit weight, ultimate tensile strength of reinforcement, and shear wave velocity of reinforced soil (GRS). The Gaussian copula is used to correlate the input random variables. The results depict that the proposed formulation is effective and precise in predicting the probability of failure (Pf) of GRSs. The performance function is evaluated only 376 times in comparison to the direct Monte-Carlo Simulation where it is evaluated at least 105 times, reducing the computation time from approximately 2 days to 25 min. To the best of author's knowledge, the proposed method is original.