Ultimate Bearing Capacity of Rectangular Footings on Inhomogeneous Soil Under Combined Loading

To accurately evaluate the ultimate bearing capacity of rectangular footings on inhomogeneous soil under combined loading is very important in engineering.Based on limit-equilibrium theory and yielding criteria of Mohr-Coulomb,the equilibrium equations can be equivalently transformed to a functional extremization,which boundary values are undetermined,by using the variational method.After introducing the boundary conditions to the functional extremization,the function of the 3-D sliding surface and the failure envelope of rectangular footings on inhomogeneous soil under combined loading are achieved.The effects of the friction angle of soil φ_i,the cohesive force c_i,the ration of L/B,the shear strength ration c_i/c_i+1 and the fluctuation of groundwater level on the ultimate bearing capacity of rectangular footings on inhomogeneous soil foundation and the failure envelop are studied.