基于IDA的高面板堆石坝抗震性能评价

抗震性能分析能够有效估计结构在地震作用下的危险性,逐渐成为抗震安全性评价的重要方法,但由于结构的复杂性,该方法在面板堆石坝方面的应用还处于起步阶段。随着强震区大量高面板堆石坝的建设,这些高坝的安全性是必须要考虑的重大问题,因此对大坝进行抗震性能分析至关重要。增量动力分析(IDA)法作为一种抗震性能分析方法,能够全面、深入地分析在不同强度地震作用下结构性能的变化。将IDA法引入到高面板堆石坝安全评价领域,建立了高面板堆石坝地震破坏性能评价方法。根据场地条件选取了15条不同的强震动记录,以地震峰值加速度PGA为地震动参数,采用坝体地震震后变形、坝坡稳定性、面板防渗体安全为抗震性能评价指标,选取合适的性能参数,建议了高面板堆石坝各评价指标的破坏等级划分标准,通过大量非线性有限元计算,得到各性能参数的地震易损性曲线,分析了大坝在不同强度地震作用下发生破坏的概率,成果可为高面板堆石坝抗震性能设计和安全风险评估提供参考和依据。

Seismic performance evaluation of high CFRDs based on incremental dynamic analysis

The seismic performance analysis can effectively estimate the risk of structures under earthquake action, so it gradually becomes the important method of seismic safety evaluation. However, this method is still in the beginning stage of application because of the complexity of CFRDs. The safety of these high dams must be seriously considered as a large number of high CFRDS are constructed, so it is very important to perform the seismic performance analysis of dams. As the seismic performance analysis method, the incremental dynamic analysis (IDA) can analyze the change of structural performance under different intensity earthquakes comprehensively and deeply. IDA is introduced into the field of safety evaluation of high CFRDs, and a seismic damage performance evaluation method is established. Fifteen different strong motion records are chosen according to the site conditions. The peak ground acceleration of earthquake is selected as the earthquake intensity factor. The dam seismic deformation, slope stability and anti-seepage of face safety are selected as the indexes of seismic performance evaluation. First, the damage grade standards of high CFRDs of each evaluation index are suggested after selecting the appropriate performance parameters. Afterwards, the seismic fragility curves of each performance parameter are acquired through a large number of nonlinear finite element calculations. Finally, the failure probability of dams under different earthquake intensities is analyzed, and the results may provide the reference and basis for the seismic performance design and safety risk assessment of high CFRDs.