Effect of Roughness on Seismic Bearing Capacity of Shallow Foundations near Slopes Using the Lower Bound Finite Element Method
Ardavan Izadi, Ahmad Foroutan Kalourazi, Reza Jamshidi Chenari
Abstract
A lower bound finite element analysis in conjunction with linear programming technique was used to evaluate the effect of soil–foundation interface roughness on the seismic limit load of shallow foundations placed in the vicinity of slopes. The approach followed in this study to take into account seismic forces is pseudostatic. The roughness factor (δ/φ) at soil–foundation interface was considered in a complete range of 0 (perfectly smooth) to 1 (fully rough) stepwise with an increment of 1/3. Furthermore, the effects of superstructure seismic inertia forces, and nonlinear programming, which is called second-order cone programming, are also addressed. The formulation of the finite element lower solution was extended for the case of pseudostatic conditions. The findings of this study have been compared with solutions reported in the literature, and the consistency of the results confirmed the formulation of the extended finite element lower bound in the presence of seismic forces. Results of the current study clearly endorse the fact that the soil–foundation interface roughness exhibits more highlighted contributions when a footing is underlain by an adjacent slope and subject to seismic loading. The results of the current study are presented in the form of table design charts.