Dam failure risk analysis of earthen and rockfill dam systems: an approach based on a combination of an Interpreted Structural Model and a Bayesian Network with parameter learning

Abstract

Abstract The risk factors of earthen and rockfill dams during operation are characterized by uncertainty, complexity, interaction, etc. The coupling of risk factors can be more accurately identified in the process of dam risk analysis. To effectively analyze the interactions between the influencing factors within the system, this paper proposes a method for analyzing the risk of earthen and rockfill dam failure based on a combination of the Interpretive Structural Model (ISM) and Bayesian network (BN) model with the parameter learning. Meanwhile, the parameter learning of the BN model using the EM algorithm reduces the subjectivity of expert evaluation. In this paper, we analyzed the interrelationships among accidents by using the ISM method through statistics and analysis of actual accident cases. We established a hierarchical structure diagram including a five-level structure to derive the direct, indirect, and fundamental factors that lead to accidents. The EM algorithm was introduced to learn Bayesian network parameters, and the probability of occurrence of each influencing factor of earthen and rockfill dam failure was obtained through BN inference, diagnosis, and sensitivity analysis. The three most important influencing factors leading to earthen and rockfill dam failure were identified as flood overtopping, insufficient spillway discharge capacity, and damage to the spillway structure. A multi-factor coupling analysis was also conducted on the earthen and rockfill dams, and the results showed that the risk of dam failure was greatly increased as a result of the coupling between the influencing factors. In addition, we also found that management issues play an important role in earthen and rockfill dam failures and are key influencing factors that cannot be ignored. This method can be effectively applied to identify and analyze the influencing factors of earthen and rockfill dam failure in China.