Bearing capacity of footings on an artificially cemented layer above weak foundation soil

Abstract

Current methods for predicting the bearing capacity of double-layer systems implicitly assume that the top layer is continuous. This paper presents a new method for calculating the bearing capacity of shallow strip footings supported by an artificially cemented soil-reinforcing layer bearing on weak foundation soil, considering its lateral extension. Tests of strip footings on a loose sandy soil, as well as numerical analysis by the finite-element method, were carried out. Two distinct types of failure were observed. In the first, the cement-reinforced soil layer punched through the loose sandy soil without showing any fissuring. In the second, after an initial settlement, the reinforcement layer broke, showing a fissure, which was located near the foundation's edge or its centre axis, depending on the reinforced layer thickness. It was found that the maximum tensile stress in the reinforcement layer was a function of the soil vertical reaction and the Tr/Hr ratio, where Tr is the horizontal distance between the edge of the footing and the edge of the reinforcement and Hr is the thickness of the reinforcement. A new calculation method for bearing capacity prediction is proposed, with the assumption that failure occurs in the natural soil.