Estimation of 3D earth pressure with inclined backfill surface considering seismic loads and suction effects

Earthquake remains the main factor in triggering the slope failures and the rigid gravity retaining wall is an effective technique in guaranteeing the slope safety. In earth pressures estimations, considering simultaneously the three-dimensional (3D) features of backfills, the suction-induced effects and the dynamic characteristics of seismic excitations warrants producing more realistic solutions. In the category of upper bound limit analysis theorem, a modified semi-analytical method for determining the seismic earth pressures of inclined unsaturated backfills is provided. Applicability and reliability of this method is varied through comparisons and the seismic responses of 3D inclined unsaturated backfills are studied. The results indicate that the 3D effect relates closely to the seismic excitations and the SWCC and can hardly be ignored in earth pressure estimations. The 3D effect varies periodically as the seismic wave propagates and is more evident in fine-grain soil slopes but is relatively less obvious in coarse-grain soil slopes.