Failure envelope of square footings resting on cohesive-frictional soils subjected to combined loading

The bearing capacity of foundations is one of the most important issues that have always attracted the attention of researchers and geotechnical engineers. In this article, the failure envelope of square footings resting on cohesive-frictional soils was investigated considering the simultaneous application of vertical, horizontal, and moment loads using finite element simulations. The effect of various factors such as soil internal friction angle, cohesion, modulus of elasticity, Poisson's ratio, unit weight and the failure criterion along with the groundwater table, the dimensions and the embedment depth of the footing were investigated. The results show that the soil friction angle has a greater effect on the size of the failure envelope than the soil cohesion. Moreover, the soil modulus of elasticity, Poisson's ratio, unit weight, and the groundwater table, have a minor effect on the size of the failure envelope compared to the footing embedment depth. By moving the footing from the ground surface to a depth equal to three times the footing width, the failure envelope enlarges more than seven times of its initial size.