Limit Analysis of Modified Pseudodynamic Lateral Earth Pressure in Anisotropic Frictional Medium Using Finite-Element and Second-Order Cone Programming

Abstract

This paper aims at analyzing the active and passive lateral earth pressures exerted on retaining walls due to the anisotropic medium of dry and noncohesive backfill subjected to the modified pseudodynamic earthquake loading. To this end, the well-established lower bound limit analysis in conjunction with the finite-element discretization method using second-order cone programming is exploited to evaluate the corresponding states of seismic earth pressures on the retaining structure. The earthquake loading is simulated by the propagation of the shear and primary waves through nonconstant inertia forces in the horizontal and vertical directions, respectively. The inherently anisotropic behavior of the soil medium is also accounted for by differentiating between the internal friction angles in different directions. Results generally show that, unlike the active state, inherent anisotropy bears a notable influence on the passive earth pressure; however, the effect of seismic loading on the lateral earth pressure is more pronounced in the active state. The dominant influence of anisotropy occurs at the critical state of seismic loading, i.e., the resonance condition. Using the results of numerical simulations, the influence of internal friction angle, soil–wall roughness, imposed wavelength, material damping, and inherent anisotropy on the lateral earth pressures is thoroughly evaluated and discussed.