Abstract: For understanding the ultimate bearing capacity and failure mechanism of soil, the finite element programming developed in laboratory based on the Mohr-Coulomb’s failure criterion considering the multiple zero-thickness interface elements is investigated. Under different geometrical conditions of failure mechanism, the ultimate bearing capacities of soil in the case studies of shallow foundation and slope foundation are particularly studied by using the mesh optimization procedure. According to the obtained results, the minimum value of upper bound by the limit analysis and that by numerical calculation are theoretically in coincidence, and the progressive failure of soil can be practically predicted.