Oblique bearing capacity of strip footings near Hoek-Brown rock slopes using the modified stress characteristics method

The ultimate bearing capacity of strip footing near rock slope (SFNRS) under oblique loads remains a theoretical challenge, as the existing analytical methods predominantly rely on a priori assumed kinematic mechanisms or numerical bound optimizations. To solve such a problem, this study proposes a rigorously modified stress characteristics method (SCM) incorporated with the generalized Hoek-Brown yield criterion. The core of proposed methodology lies in establishing a strictly statically admissible stress field that fundamentally accommodates complex oblique boundary conditions and variable footing setback distances. Based on the typical boundary value problems (BVPs) and the principle of minimum bearing capacity, the proposed framework autonomously captures the spontaneous transition among five distinct failure modes, completely eliminating the dependence on predefined failure patterns. The probable failure mode of SFNRS alters according to the different boundary conditions, which include the footing setback distance, load inclination, and slope geometry. Furthermore, a comprehensive parametric analysis reveals that the geological strength index ( GSI ) essentially improves the ultimate bearing capacity, while an increase in the load inclination angle significantly accelerates the transition of the critical slip surface from overall sliding failure to localized face failure, or even Prandtl’s foundation failure. Furthermore, quantitative thresholds for the critical setback distance and the critical slope height under oblique loads are established, providing novel theoretical insights and practical design guidelines for the safe placement of foundations adjacent to rock slopes.