Upper-Bound Axisymmetric Limit Analysis Using the Mohr-Coulomb Yield Criterion, Finite Elements, and Linear Optimization

Abstract

An upper-bound limit analysis formulation has been presented for solving an axisymmetric geomechanics stability problem using the Mohr-Coulomb failure criterion in conjunction with finite elements and linear programming. The method is based on the application of the von Karman hypothesis, and it requires only nodal velocities as the basic unknown variables. The computational effort needed to solve the axisymmetric problem becomes almost the same as that required for an equivalent plane strain case. By using the proposed method, bearing capacity factors were obtained for a circular footing placed over a cohesive-frictional soil medium. Nodal velocity patterns were also examined. Necessary comparisons have also been given to examine the usefulness of the proposed formulation.