壩的風險評估之越南案例研究

Abstract

In Vietnam, embankment dams have been developed for over 60 years. Therefore, the safety concerns of aging dams are one of the challenges, which the hydraulic field faces at this time and in the near future. There are two approaches to dam safety, namely, standard based and risk based approaches. Although risk assessment is standard practice for dam safety, this term is relatively new to hydraulic engineers in Vietnam. The procedure of risk assessment is presented in this M.S. Thesis, which consists of qualitative and quantitative assessments and consequences estimation. Suoi Mo dam is used as a case study for applying risk assessment in Vietnam because it has similar dimension and characteristics such as height, reservoir capacity and structure to approximately 300 of 500 large dams in Vietnam. Several methods can be used in each process of risk assessment. For qualitative assessment, failure modes & effects analysis (FMEA) is the state of practice method that is used in identifying initial failure. Historical performance and event tree analysis are used to analyze quantitative risks, and then the flood severity method developed by Graham (1999) is applied to estimate the possible loss of lives. The probability of the loss of lives during each failure mode for Suoi Mo dam provides important information for the decision maker in coming up with the solutions for unexpected situations. A lack of useful data is one of the barriers to successful application of the actual solutions, causing the reliability of the assessment results to be decreased.