峡谷区重力坝岸坡坝段动力稳定性评估方法

从概率的观点出发，结合确定性矢量和安全系数方法，对设计基准期内随机地震条件下的重力坝岸坡坝段动力抗滑稳定性评估方法问题进行了初步探讨。首先，基于确定性动力时程分析法，得出坝段抗滑矢量和安全度时程曲线，评价一次确定性设计地震作用下的坝体稳定；然后，考虑基准期设计烈度下地震的随机性，进行坝体动力稳定的可靠度分析。通过Gram-Charlier级数拟合法和随机加权最大熵法，得到坝体动力稳定安全度时变曲线中最小值的概率分布函数及其动力可靠度；最后，结合确定性和概率性分析结果，综合评价设计基准期内地震作用下的坝体抗滑稳定性。工程实例分析结果表明，采用确定性与概率性结合的互补方法，能够进一步认识动力稳定分析中安全裕度的合理性评价问题，进而更加合理地评估整个设计基准期内重力坝的动力抗滑稳定性。

Seismic stability evaluation for bank sections of gravity dams in gorge area

From the viewpoint of probability theory, combined with the deterministic vector sum method, the stability evaluation methods are studied for the bank sections of gravity dam under random seismic loads. Firstly, deterministic stability evaluation is made through the history curve of safety factors, which is obtained by dynamic vector sum method, under a certain seismic load. Secondly, the probability density function(PDF) of the minimum value of dynamic stability safety factors and the dynamic reliability are got through the Gram-Charlier series fitting method and the weighted maximum entropy method under random seismic loads. Thirdly, comprehensive evaluation is made by both deterministic results and probabilistic ones during the whole design period. The example results show that the deterministic and probabilistic methods can complement each other to make a comprehensive seismic stability evaluation for the bank sections of the gravity dam during the whole design period.