混凝土坝抗震安全评价指标和方法研究

以提出混凝土坝整体抗震性能评价指标体系和方法框架为目标,分析研究了美国水工建筑物设计规范(EREM)基于性能目标的抗震评价方法、评价标准、定量化性能指标,同时对国内外相关成果进行了对比分析。针对高混凝土坝的最大设计地震(MDE)的设防水准以及最大可信地震(MCE)的安全目标,为了更好地评价地震动作用下结构性态,应注重定量化评估坝体—地基—库水的整体效应,以及应力和变形响应的累积效应,结合现有的高混凝土坝的抗震评估,进行线弹性评价和非线性响应分析。线弹性评价预测应引入USACE评价程序和判别准则中的结构需求能力比、超线弹性累计时间和性能曲线等定量化指标,再结合现行规范从坝体关键部位、横缝等方面进行非线性响应分析修正分步实施,建立混凝土高坝抗震性能定量化评价框架。研究成果为混凝土坝抗震性能评价提供参考。

A preliminary study on performance-based seismic safety evaluation index of concrete dams

In order to propose the evaluation index system and method framework of the whole seismic performance of concrete dam， the seismic evaluation methods， evaluation criteria， and quantitative performance indicators of USACE earthquake design and evaluation of concrete hydraulic structures were studied in the paper， and the domestic and foreign related results were compared and analyzed. According to the safety objectives of the maximum design earthquake （MDE） and the maximum credible earthquake （MCE） of high concrete dams， in order to better evaluate the structural behavior under ground motion， it is suggested that quantitative assessment of integral effect with dam-foundation-reservoir water and the cumulative effect of stress and deformation response were emphasized to evaluate dam structural behavior with seismic loading. To form framework of quantitative evaluation of seismic performance of high concrete dams， it should be evaluated with elastic computation and further nonlinear response analysis， combined with the existing seismic evaluation of the high concrete dam， the linear elasticity prediction should be introduced into evaluation procedure and judgment criterion with quantitative index of USACE based on the demand-capacity ratio， the cumulative overstress duration and the spatial extent of overstressed regions， then combined with existing norms， corrected by the nonlinear response analyses from the key parts of dams and contraction joints. The research results provide a reference for the evaluation of seismic performance of concrete dam.