INFLUENCES OF A NONLINEAR FAILURE CRITERION ON PASSIVE EARTH PRESSURE

The passive earth pressure problem is studied by means of the kinematical approach of limit analysis theory. The filling soil behind rigid retaining wall is perfectly plastic, whose failure is governed by a nonlinear Mohr-Coulomb failure criterion. Three kinds of knematically admissible failure mechanisms are considered for the calculation schemes. The main differences among the three failure mechanisms are velocity vectors between soil and wall. The objective functions are obtained by equating the work rate of external force to internal dissipation along the velocity discontinuities. The upper bound solutions are presented by applying a nonlinear sequential quadratic programming(SQP)algorithm. From the numerical results, it can be seen that the nonlinear failure parameter has a significant effect on the passive earth pressure and the three translational failure mechanisms are equivalent for computing passive earth pressures. If the nonlinear Mohr-Coulomb yield criterion turns into a linear Mohr-Coulomb yield criterion, then the solutions presented in this paper agree well with available predictions.