Seismic analysis of 3D active earth pressure for unsaturated backfill

Abstract

A new procedure is proposed for evaluating active earth pressure subjected to earthquake vibration for three-dimensional (3D) unsaturated backfills comprised of cohesive soils, which is conducted by developing an upper bound analysis. The impact of diverse water tables on unsaturated soil-wall stability is incorporated into the comprehensive analysis, and it turns out to be indirect by exerting influence on pore-water pressure and matric suction. A 3D horn-like failure mode is adopted to characterize the collapse of unsaturated backfills. The explicit expression of seismic active earth pressure can be derived by the principle of energy dissipation, where the seismic effect is assembled into the present study as a uniformly distributed inertia force. Comparison results with previously published literature show good agreement. Parametric studies are further performed to investigate the influences of several parameters on the retaining wall. This approach provides a useful tool for reflecting the true response behaviors of critical failure mechanism and evaluating the stability of unsaturated cohesive backfills.