考虑地震波随机性及水位影响的高土石坝易损性研究

Seismic fragility assessment of high earth-rockfill dams considering the seismic wave randomness and water level

考虑地震动输入数量及不同水位工况下的流固耦合影响,采用弹塑性模型非线性有限元方法对国内某高土石坝进行动力分析,再通过多样条分析(MSA)法对该坝地震易损性研究。根据场地条件选取40条地震波,并对高土石坝震害等级进行划分,选取坝体相对震陷率作为易损性极限状态指标;采用动力固结有限元程序SWANDYNE II对大坝进行动力计算,再采用MSA法得到地震易损性曲线。通过不同地震波数量的易损性方程参数分析,确定地震波合适的输入数量。通过对不同水位和地震动强度作用下的高土石坝三维易损性曲线发现,在相同地震作用下,随着水位的升高,大坝不同等级相应的破坏概率增大。综合考虑不同水位和地震动输入数量对高土石坝地震易损性的影响,可为高土石坝抗震安全评估提供参考依据。

Considering the number of input ground motions and the fluid-solid coupling of high earth rock dams under different water levels, the dynamic analysis of a high earth rock dam in China was carried out by using an elasto-plastic model and nonlinear finite element method. Then the seismic fragility assessment of the dam was investigated based on the multi samples analysis(MSA) method. 40 seismic waves were selected according to the site condition, and the earthquake damage level of the high earth rock dam was divided. The relative seismic subsidence rate of the dam was selected as the index of the fragility limit state. The dynamic consolidation finite element program SWANDYNE Ⅱ was used in the dynamic analysis of the dam, and the seismic fragility curve was obtained by the MSA method. Through analyzing the fragility equation parameters under different seismic waves, the appropriate number of seismic waves was determined. Through the 3D fragility curves of the high earth rock dam considering the influences of different water level and ground motion, it is shown that the damage probability under different damage levels increases with the rise of water level under the same earthquake. Considering the influences of different water level and seismic waves, the results provide a reference to the seismic safety assessment of high earth rock dams.