Bearing Capacity of Footings on Unsaturated Uniform Slopes

Abstract

Significant research has been conducted on the stability of footings on slopes under dry conditions. However, there are only limited studies under unsaturated conditions. In this paper, the load-bearing capacity of a rigid strip footing placed on the surface of uniform slopes under various suction profiles was determined. Parametric studies were carried out for simulated soil to assess the load-bearing capacity of the footing placed at various setbacks (b) from the edge of a slope (0, 1, 2, 3, and 4 m) considering different soil strengths and slope inclinations (β): 0°, 15°, 30°, 45°, and 60°. The analyses included Nc and Nγ problems. The solutions demonstrated upper limits for associative materials. The numerical analysis exhibited, as expected, direct and inverse relationships between b and β against ultimate bearing capacity, respectively. However, the combined effect of b and β at different suction profiles was found to be significant. The increase in ultimate bearing capacity, attributed to the effect of suction stress, was observed to be very significant in the transition zone. The influence of the air entry value was also examined, revealing a significant effect. Based on the numerical analysis, a series of Nc and Nγ factors were proposed that envision the literature's need for stability assessment of footings placed on unsaturated uniform slopes.