Lower bound limit analysis of wedge stability using block element method

A lower bound limit analysis approach based on the block element method is proposed to analyze wedge stability problem. The search for the maximum value of the factor of safety is set up as a nonlinear programming problem. Sequential quadratic programming (SQP) algorithm from a reasonable initial value is applied to obtain the optimal solution. This approach provides a strict lower bound solution considering the sliding mode and rotation effect simultaneously. The deviations of the factor of safety between the present and traditional limit equilibrium methods are positively correlated with both the friction angle and the dip of the discontinuity surface.