Elasto-viscoplastic simulation of bearing capacity characteristics of strip footing on reinforced sand

A nonlinear FEM analysis incorporating an elasto-viscoplastic constitutive model for sand that has been developed based on results from comprehensive laboratory stress-strain tests including plane strain compression tests is described. A series of plane strain laboratory model tests on the bearing capacity on a model strip footing (10 cm-wide) performed on unreinforced and reinforced level sand grounds were simulated by the FEM. The simulated footing load and settlement relation and failure mechanism in the unreinforced and reinforced sand grounds were compared with the measured ones. It is reported that the proposed FEM analysis method can simulate very well the test results, including the effects of reinforcing. It is one of the characteristic features of the proposed numerical analysis method that the footing and settlement behaviour around the peak footing load state and the one in the post-peak regime can be simulated in a very stable manner. It is shown that this is due largely to that the realistic viscous properties of sand that are properly modeled are incorporated in the FEM analysis.