Recent studies on combined loading of shallow foundations employ a force-resultant model as a means of evaluating the state of yielding. The development of soil rupture in relation to this said model has, however, not been investigated particularly in cases of cohesionless soils. In response, a surface strip footing is subjected to vertical, horizontal, and moment-rotational displacements to determine a state of yielding on dry, dense sand. An image-based deformational analysis is used in synch with recorded load-displacement responses, to demonstrate correctly the mechanisms of soil deformation at every load state leading to and ensuing this said yielding.
A one-sided rupture slip line, which characterizes the plastic failure of a shallow foundation under an eccentric or inclined load, was first presented by Meyerhof (1951, 1953). Jumikis (1956, 1961) experimentally evaluated this slip line by imparting oblique loads on strip footings above dry sand and determining the volume of ruptured soil after the footing has completely collapsed. In these studies, the slip line was assessed only under the condition of a plastic failure, thereby adhering to an assumption that yielding itself coincides with full rupture of the soil. However, results of subsequent bearing capacity tests on dense sand by Yamaguchi et al. (1976) have exemplified that until the point of yielding, soil rupture was not fully developed but that strains along a supposed slip line were rather observed to decay with increasing distance from line of direct load on the footing. This led to the characterization of a progressive failure phenomenon in granular materials. One important aspect addressed by such a phenomenon is the premature representation of state of soil rupture or the gross overestimation of state of yielding by the conventional soil peak strength given by the angle of friction,.
