高坝大库一旦溃决失事，将对下游造成严重的灾害和巨大的损失，国内外已发生多起地震、洪水等自然灾害引发的溃坝事件，其后果触目惊心。及时准确地预测自然灾害作用下的溃坝风险，并有效进行风险决策具有极其重要的研究意义。目前该领域的研究还较为薄弱, 亟需引入新的大坝风险评估方法和技术。本项目以地震和洪水为溃坝风险的自然风险源中的主要灾种，采用实地调研、理论分析、数学模型相结合的方法，围绕2个关键科学问题：以D-S证据理论为基础的溃坝风险评估理论方法与模型体系的开发；新溃坝风险评估理论方法与模型体系的实用性，系统开展大坝在多灾种复合作用下的溃坝风险评估研究。本项目将引入和发展D-S证据理论推导出地震与洪水复合作用下溃坝风险评估指标体系数据融合值的理论公式和风险量化公式，建立多源信息数据融合形式的风险量化模型，制定风险度量等级，进行风险评价和区划。进行实证研究，以验证新方法、模型的有效性和实用性。

Once dam failure happen, it will bring serious disaster and huge loss. Historically, dam break events caused by earthquake, flood or other natural hazards have happened all over the world with shocking consequences. Therefore, it is of extremely vital significance to forecast timely and accurately the dam break risk under the action of natural hazards and to make effective risk decisions. At present, the research in this field is still comparatively weak, it is urgent to introduce new methods and techniques of dam break risk assessment. Based on our previous research results on reservoir dams in southwest mountain area, China, this proposal regards earthquake and flood as the main disaster types of natural risk sources. Field researches, theoretical analyses and mathematical models are to be carried out to solve 2 key scientific problems concerned in this proposal, namely, (1) develop a new theoretical method and model system of dam break risk assessment based on Dempster-Shafer (D-S) evidence theory, (2) the usefulness of the new theoretical method and model system of dam break risk assessment, and to systematically assess the dam break risk under the action of several natural hazard types. This proposal aims to introduce and develop D-S evidence theory with the keynotes of improved combination rules of evidence and basic probability assignment (BPA) functions, to derive the theoretical formula of data combination of dam break risk indicator system and the risk quantification formula, to build the risk quantification model of data combination of multi-source information, to set up risk measurement level, and to make risk evaluation and risk zonation. This proposal also take some typical dams as examples to assess the dam break risk under the composite action of earthquake and flood, to prove the effectiveness and practicability of the proposed new theoretical method and model system of dam break risk assessment based on Dempster-Shafer (D-S) evidence theory.