Abstract: The values of anti-slide strength parameters have important influence on the calculation of slope stability, and back analysis is an effective method to obtain the anti-slide strength parameters quickly and accurately. In this article, two specific equations for anti-slide strength parameters and factor of safety are established based on the results of slope stability analysis and the relationship between anti-slide strength parameters and the corresponding critical slip surface. Thus the results of back analysis can be obtained when the factor of safety or a strength parameter is known for the given critical slip surface. For the sake of convenient calculation, the explicit expressions for back analysis of parameters are deduced by adopting the limit equilibrium Swedish method to analyze slope stability in consideration of a variety of factors. Furthermore, the critical slip surface is assumed to be circular and is determined by survey methods. Through comparison with some examples, the correctness of this method is verified. Moreover, researches on the parameter analysis show that the larger spacing of monitoring sites on critical slip surface, the smaller effect of position error of monitoring sites on the inversion result. Application of the present method to engineering example illustrates its practicability.

Key words: critical slip surface, factor of safety, slope stability, strength parameters, back analysis, limit equilibrium