Ultimate Bearing Capacity of Strip Foundations with Inclined Eccentric Loading in Cavity-Containing Rock Masses
摘要
Adaptive finite element limit analysis was used to bracket the ultimate bearing capacity of a strip foundation of width B resting on a generalized Hoek–Brown rock mass containing a rectangular cavity. Upper- and lower-bound solutions were combined to compute a bearing-capacity reduction factor Rc relative to intact rock. The cavity was parameterised by width X, height Y, depth H, and horizontal offset S. The applied load was parameterised by eccentricity e and inclination angle β. Parametric analyses evaluated Rc and failure mechanisms over ranges of S/B, H/B, X/B, Y/B, e/B, and β. Rock-mass inputs included geological strength index GSI, intact rock uniaxial compressive strength σci, Hoek–Brown material constant mi, and unit weight γ. Bearing capacity decreased as the cavity approached the footing centerline, as X/B or Y/B increased, and as H/B decreased. Load eccentricity and inclination promoted asymmetric failure surfaces that propagated from the footing edge toward the cavity roof and sidewalls. When H/B or S/B was sufficiently large, Rc approached 1 and failure localised beneath the footing without intersecting the cavity. The results quantified cavity effects on foundations in karstified rock masses and supported engineering evaluation of strip foundations above subsurface voids.