Coupled Bearing Capacity Factor for Strip Foundations on Cohesive-Frictional Soil Slopes under Static and Seismic Conditions

Abstract

This paper investigates the bearing capacity of strip foundations resting on a cohesive-frictional soil sloping ground under both static and seismic conditions by applying the kinematic theorem of limit analysis. With the consideration of a composite collapse mechanism involving a generalized continually deforming shear zone, analytical expressions are established by incorporating the coupled influence of the soil resistance contributed by the cohesion, angle of internal friction, and self-weight of the soil mass. The loading conditions owing to inertia forces of supporting structures and the changes in the body forces of the supporting soil medium occurred during an earthquake are included in the analysis based on a pseudostatic approach. Rigorous upper-bound solutions are presented in the nondimensional form as charts and tables for the practical range of parameters that are normally encountered in the field. Additionally, by extending the concept of slope stability, a closed-form expression is proposed for computing the limiting values of horizontal seismic acceleration coefficients beyond which the sloping ground becomes unstable. The importance of the consideration of coupling effects of the soil resistance toward evaluating the static and seismic bearing capacity of foundations on the sloping ground over conventional approaches is discussed.