Reliability Analysis for the Surface Sliding Failure of Gravity Dam

Abstract

Allowance safety factor design (AFSD) as a traditional method of anti-sliding stability analysis has many limitations. For instance, it cannot consider the uncertainty of variables and make risk assessment. To make up for these shortcomings, this paper provides a simple method to investigate the real failure probability of allowable safety factor $K_{a}$ through the reliability theory and gives the recommended value of the $K_{a}$. The real safety level of the $K_{a}$ can be represented by its corresponding reliability index distribution, which is composed of the reliability indexes calculated by a group of gravity dams with the same safety factor. Using 90% to ensure the conservative evaluation of the target reliability index $\beta_{t}$ of such distribution, we can get the $\beta_{t}$ corresponding to the $K_{a}$, which is able to roughly assess the risk degree of the $K_{a}$. Moreover, the $K_{a}$ can be calibrated according to the $\beta_{t}$ provided by the engineering specification.