Study on Wide-Deep Strip Foundations Resting on Unsaturated Soils

Abstract

With the development of high-rise buildings, wide and deep foundations have been extensively applied to practical projects during the last several decades. This research aims to develop a solution that applies to wide and deep foundations with the necessary accuracy. Considering the influences of matric suction, adjusted soil parameters, wall friction, and stress strength nonlinearities from high matric suction, a solution for estimating the bearing capacity of strip foundations on unsaturated soils is presented based on the unified strength theory of unsaturated soils and the upper bound method of limit analysis. The validity and applicability of the solution are verified compared with Meyerhof's solution and Zhang's solution. The influences of the breadth, depth/breadth ratio, wall friction, matric suction, and adjustment factor of soil parameters upon the bearing capacity are discussed. Furthermore, a simplified chart-lookup method is presented for practical application. Because it includes the wall friction and assumes only a single failure pattern in derivation, the solution developed for the bearing capacity of strip foundations applies to both shallow and deep foundations.