Effects of soil non-linearity on the seismic response of restrained retaining walls

Abstract

Retaining structures characterised by high rigidity and various kinematic constraints, such as bridge abutments and basement walls, do not permit limit-equilibrium conditions to be developed. Therefore, according to contemporary norms and geotechnical design practice worldwide, they are most frequently designed utilising the elasticity-based methods, which usually lead to substantially increased dynamic earth pressures. The present paper aims to examine how and to what extent the potentially developed non-linearity of the retained soil may affect: (a) the dynamic distress of a rigid fixed-base retaining wall, and (b) the seismic response of the retained soil layer. For this purpose, a parametric study is conducted which is based on two-dimensional dynamic finite-element analyses using various idealised or real seismic excitations scaled to several intensity levels. Soil non-linearity is realistically taken into account via the commonly used equivalent-linear approach. The results of the present study demonstrate that potential non-linearity of a soil layer retained by a rigid fixed-base wall alters the soil amplification pattern behind the wall and leads to dynamic earth pressures usually lower than those proposed by seismic norms.