Kinematic analysis of seismic slope stability with a discretisation technique and pseudo-dynamic approach: a new perspective

摘要

Slopes are more vulnerable to instability when subjected to earthquake ground shaking. In order to account for the dynamic forces induced by ground shaking, a novel procedure is introduced in this paper to estimate slope stability under the ultimate limit state with a combination of pseudo-dynamic approach and discretisation technique. A pseudo-dynamic approach is adopted which allows the introduction of an arbitrary time history of seismic accelerations. In order to consider non-uniformity of soil properties of the slope, the discretisation technique is proposed with the aim of generating a potential failure mechanism with discretised points by forward difference 'point-to-point' method. Infinitesimal trapezoidal elements composed of successive discretised points and sloping surface are selected for kinematic analysis. In this way, the problem is decomposed into separate components, which aids computational effort. The upper-bound solutions of limiting surcharge loading and yield seismic acceleration are thereafter obtained with the equilibrium of total external work rate and internal energy dissipation rate through the summation from all infinitesimal elements. The methodology is validated through comparison with its degraded approach and conventional upper-bound analysis. Further parametric study is also carried out to highlight the influence of the various soil and loading parameters on the critical seismic acceleration.