Abstract：Based on genetic algorithm and Bishop¢s method，searching methods of circular sliding surface applied widely in engineering for the critical failure surface are presented and the minimal safety factor is located accordingly. The searching critical failure surface of a general soil slope is difficult as the objective function for the factor of safety is non-convex and multiple minimal exist in general，but genetic algorithm works well on optimization for multiple extremes. Traditional methods use constant upper and lower bounds of the design variables，which would enlarge searching band and create many unacceptable solutions to meet the requirements on kinematically acceptable mechanism. These solutions need be removed，which will cause efficiency loss for searching. For this problem，real-valued genetic algorithm is proposed and the constraints of the problem are transformed to the determination of the dynamic upper and lower bounds of the design variables. So，searching band is reduced and the efficiency for searching is improved. The critical failure surface can then be located with high precision with reasonable calculation time under the presented proposal. Numerical example shows that analyzing method of the slope stability based on the genetic algorithm is a global optimal procedure that can overcome the drawbacks of local optimum widely existing in classical searching methods. The analytical result is satisfactory.
