Seismic Bearing Capacity of a Circular Footing on a Heterogeneous Cohesive Soil

Abstract

ABSTRACT This study concerns the determination of the seismic bearing capacity of a circular footing resting on a purely cohesive heterogeneous soil layer. The problem is treated using the kinematic approach of the Yield Design theory. The soil strength is modelled by the Tresca criterion with C0 the cohesion at the soil surface and G the vertical cohesion gradient. The loading process of the system is described by four loading parameters: an inclined force (N: vertical component, V: horizontal component), a moment (M) acting at the center of the footing and horizontal uniform inertial forces (Fh) acting in the soil volume during the seismic excitation. Two cases are considered for the soil: a soil with an infinite tensile strength and a soil with zero tensile strength. The soil-footing interface is considered purely cohesive with zero tensile strength. The study presents optimal upper bounds for the ultimate combinations of the dimensionless loading parameters (N, V, M, Fh) by the examination of a series of three-dimensional virtual kinematic mechanisms of failure. The results are presented in the form of surfaces in the space of the parameters (N, V, M) for a range of values of Fh.