Experimental and numerical study of weak soil layer effects on ultimate bearing capacity of strip foundations resting on inclined layered soil masses

The construction of structures near slopes has nowadays become inevitable. and several theoretical models have been proposed to estimate the ultimate bearing capacity of foundations located on slops. However, slopes with inclined layered soils have so far remained insufficiently explored. This study examines the influence of slope angle and strip foundation location on the ultimate bearing capacity of such slopes through experimental and numerical analyses. The results indicate that a decrease in slope angle and an increase in setback distance (i.e., the horizontal distance from the foundation edge to the slope crest) enhance the ultimate bearing capacity. Additionally, compared to homogeneous slopes with similar dimensions and setback distances, slopes with a weak offset layer (a weak layer in the foreground) and those with a weak interlayer exhibit a reduction in ultimate bearing capacity. Specifically, for slopes with angles of 30, 45, and 60, reductions of approximately 8%, 20%, and 31% were observed for weak offset layers, while reductions of 10%, 19%, and 28% were noted for weak interlayers. However, as the setback distance increases, these differences diminish following a quadratic function. At a distance of approximately four to six times the foundation width, the ultimate bearing capacity becomes comparable to that of a strip foundation situated on level ground.