高拱坝失效风险评价研究现状与存在问题分析

Analysis of the existing situations and problems in failure risk evaluation of high arch dams

在总结混凝土高拱坝失效风险源、失效分类、失效模式内涵、主要失效模式甄别、单个失效模式下失效概率及具有多个失效模式高拱坝系统失效概率的研究方法、风险衡量指标选取及计算、容许风险确定及风险评价准则、控制与降低风险管理措施等基础上,指出混凝土高拱坝失效风险评价存在的主要问题是:风险衡量指标的定量计算研究不够深入,结构失效导致溃坝未得到特别重视,失效判据及容许风险确定的理论依据不足,失效模式的定义缺乏科学性等。针对这些存在问题提出了一些解决途径和建议:失效模式应基于可靠度理论从破坏机理角度进行科学定义,需要深入探索能分别定量计算具有显性及隐性状态函数失效模式下失效概率的方法,需要结合中国国情特别是发展阶段定位、生命价值观等确定容许风险标准,更需要尽快建立混凝土高拱坝溃坝风险评价的科学理论体系和实用方法。

This paper reviews various factors in the failure risk evaluation of high-arch concrete dam： sources of failure risk,failure classification,connotation of failure modes,identification of main failure modes,the methods of research on failure probability in single mode and multiple modes,selection and calculation of the risk evaluation indexes,determination of tolerable risk,risk assessment criteria,and managerial measures in controlling and reducing the risk,etc.Analysis on these factors reveals the major existing problems in failure risk evaluation： the study of quantitative calculation of risk evaluation indexes is not in enough depth;no special attention has been paid to the failure type caused by structural failure;the theories for failure identification and allowable risk determination are inadequate;the definition of failure modes is not enough scientifically strict.Aiming at a solution to these problems this paper makes the following suggestions： failure mode should be scientifically defined in the perspective of failure mechanism based on the reliability theory;it is necessary to probe in depth the method of quantitatively calculating the failure probability for the modes of both explicit and inexplicit failure functions;allowable risk standards should be established by considering the actual situations of China,particularly the stage of development and the value of human life.Above all,it is necessary and urgent to establish a system of scientific theories and practical techniques for failure risk evaluation of high-arch concrete dam.