Influence of failure mechanism on seismic bearing capacity factors for shallow foundations near slopes

Abstract

The bearing capacity of shallow foundations may decrease when located near slopes, particularly under seismic conditions. However, there is limited work that isolates the destabilising influences of seismicity and finite slope geometry on ultimate bearing capacity in terms of conventional bearing capacity factors. Herein, analytical solutions based on upper-bound kinematic limit analysis are used to isolate both the mechanism of failure and bearing capacity factors (Nc, Nγ and Nq) for shallow foundations near slopes subject to seismic action without using principles of superposition. The analytical solutions of ultimate seismic bearing capacity show good agreement and accuracy compared with numerical results. Seismic bearing capacity factors are assessed considering transitions in failure mechanism, soil properties and finite configurations of slope and footing geometry. The results presented demonstrate significant non-linearity in bearing capacity factors that have not been previously demonstrated, primarily owing to the transition in governing mechanism with geometry, shear strength or seismic loading. This study shows that the isolation of bearing capacity factors without superposition is possible considering slope and footing geometry, and is greatly influenced by the failure mechanism.