Abstract: A combination method of the trial-and-error and the back-analysis is used to evaluate values of c and φ of the sliding body within the rock and soil mass in the sliding zone. This paper presents the analysis of a complex landslide in Siwan Village, Longtian Township, Chengkou County of Chongqing. The stability analysis of 6 groups of profiles within the landslide area was performed. The difference between the implicit and explicit solutions of the unbalanced thrust method was compared. The results show that, when the explicit solution method is used, the analysis result is slightly greater than 1.0, the implicit solution method should be reviewed to prevent the evaluation deviation from being too large; when the explicit solution method is far greater than 1.0, the implicit solution method is also recommended. Since the simplified conditions of the explicit solution no longer meets the solution requirements, additional check should be performed. From the perspective of theoretical analysis and engineering practice, the conclusion can provide a reference for the stability analysis of landslide. 

Key words: unbalanced thrust method, back-analysis, implicit solution, explicit solution, stability