Abstract: According to the requirements in Section 5.2.7.3 of the new "Geotechnical Engineering Investigation Specifications (GB50021-2009), the back analysis should be used to examine the strength parameters of the sliding surface. However, the specifications do not explicitly suggest the back analysis procedure. This paper presents a case history of the application of the back analysis method in determining the strength parameters of a sliding surface. It is concluded that the appropriate strength parameters could be obtained by the combination of back analysis and the stability analysis of the sliding surface.

Key words: Back Analysis, Sliding Surface, Strength Parameters of Sliding Surface