Slope Reliability Analysis Considering Site-Specific Performance Information

The performance of a slope, such as surviving a certain groundwater condition, can be viewed as the outcome of a full-scale test performed directly on the slope and may provide valuable information for safety assessment, upgrading analysis, and repair design of the slope. Performance information can be divided into two types: (1) the slope survived a certain state, and (2) the slope failed at a certain state. This paper illustrates two methods for slope reliability analysis considering site-specific performance information, i.e., an indirect method based on back-analysis of the performance information, and a direct method, in which the back-analysis procedure is bypassed. The two methods are theoretically the same but different in implementation details. As examples, an existing slope for safety assessment and a failed slope to be repaired are studied in this paper. Considering the past survival information increases the reliability of the slope. The increase in reliability is larger if the slope survives a more critical state. Thus, ignoring the survival information may result in uneconomical decisions. In contrast, ignoring the failure information may either underestimate or overestimate the reliability of a slope. As a result, neglecting the past failure information may lead to unsafe or uneconomical decisions.