Undrained vertical bearing capacity factors for shallow foundations

The undrained vertical bearing capacity of a shallow foundation is a fundamental problem in geotechnics. Bearing capacity factors based on analytical and numerical methods have been published for strip and circular, surface and shallowly embedded foundations, with rough and smooth foundation-soil interfaces in soils with uniform and linearly increasing shear strength profiles - although not comprehensively for all combinations. Furthermore, in the case of limit analysis solutions, considerable disparity can exist between upper and lower bound solutions for some foundation and soil conditions. This letter presents a coherent set of bearing capacity factors based on finite element and finite-element limit analysis, for strip and circular shallow foundations across a practical range of foundation embedment ratio, foundation-soil interface roughness and soil shear strength heterogeneity.