An Upper Bound Solution to Undrained Bearing Capacity of Rigid Strip Footings Near Slopes

Abstract

The undrained ultimate bearing capacity of rigid strip footings near slopes is one of important problems in practical foundation engineering in soft clay. To solve the bearing capacity conveniently and easily, a calculation method for the undrained bearing capacity is proposed using the upper bound limit analysis. A bilateral failure mechanism is provided and involved in the analysis, and two failure modes including slope face failure and below-toe failure are pointed out considering the location relationship between the critical slip surface and the slope toe. The upper bound solution of the undrained bearing capacity based on the failure mechanism is carried specifically out via the optimization algorithm. Analysis of some typical examples shows that the results calculated by the proposed method agree well with those obtained using other analytical and numerical methods. The maximum error is about 10%. Cohesion of slope soil, slope angle, horizontal setback distance of strip footing from the slope crest, slope height, surcharge on the slope top level, and the footing depth have great influence on the undrained bearing capacity.