3D Stability and Failure Mechanism of Undrained Clay Slopes Subjected to Seismic Load

Seismic stability of soil slope is one of challenging problems in soil dynamics. In this study, the stability of three-dimensional (3D) undrained clay slopes subjected to pseudo-static seismic load is investigated by utilising the finite element limit analysis (FELA) of rigorous upper and lower bounds. The FELA solutions are normalised and presented by a seismic stability number influenced by four dimensionless variables, namely, a depth factor, a slope length ratio, a slope inclination and a horizontal seismic acceleration coefficient. The impacts of a horizontal seismic acceleration coefficient on the mechanisms of 3D slope failures based on FELA are examined and discussed for the first time. The respective influence and sensitivity of each design parameter on the seismic stability number of 3D undrained slopes under the influence of seismic load is investigated using the multivariate adaptive regression spline analysis. A predicted equation that can be used to effectively estimate the seismic stability number, which can be of great interest to practitioners, is also developed.