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

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.