Failure Mechanism of Slopes Subjected to Embedded Strip Footing Loads under Seismic Conditions

Abstract

The stability of slopes subjected to vertical embedded strip footing loads under static and seismic conditions was investigated. The pseudostatic method was considered to represent an earthquake load. Two-dimensional lower-bound finite-element limit analysis (LB-FELA) and the strength reduction method (SRM) were employed to investigate the stability and failure mechanisms of the slopes subjected to the footing loads. It was found that the factor of safety (FOS) started to decrease rapidly after a certain load (defined as a threshold load). The critical location of the footing on the slope (where the FOS was at a minimum) was examined. In addition, a series of numerical analyses were carried out to check the effect of edge distance on slope stability. Changes in the FOS were evaluated for a particular footing edge distance for varying slope angles. The effects of variation in the shear strength parameters and the location of the water table on the slope stability under footing loads were also examined. It was found that the effect of loading intensity on the FOS was significant for gentle slopes, with this effect decreasing for steeper slopes. The influence of footing width on the FOS, for a given slope angle and loading intensity, was also insignificant. The footing near the slip surface at the top of the slope was the most critical location. The effect of the water table on the FOS diminished as the loading intensity on the footing increased. To demonstrate the practical application of this study, we also examined the slope failure that occurred during the 2011 Tohoku, Japan, earthquake.