主余震序列作用下面板堆石坝应变能及易损性分析

Strain Energy and Vulnerability Analysis of Faced Rockfill Dam Under Main Aftershock Sequence

为研究主余震序列作用下面板堆石坝的抗震性能,定量分析主余震序列对坝体结构破坏的影响,基于增量动力分析(IDA),分别以总应变能及弹性应变能与总应变能的最大比值作为结构性能指标,得到该坝体在主余震序列作用下的应变能时程曲线和易损性曲线,研究主余震序列对该坝体抗震性能的影响。结果表明,主余震序列作用下的应变能时程曲线位于单一主震上方,表明主余震序列会加剧该坝体的破坏程度,特别是坝体在自振周期下的谱加速度Sa(T1)值较大时,所引起的坝体破坏程度更加显著;主余震序列作用下的易损性曲线位于单一主震上方,表明主余震序列作用下该坝体的破坏概率大于单一主震破坏概率,且主余震序列作用下的破坏概率与主震强度有关,主震强度越高,主余震序列作用下的破坏概率越大。

In order to study the seismic performance of faced rockfill dam under the action of main aftershock sequence,the impact of the main aftershock sequence on the dam structure damage is analyzed quantitatively.Based on incremental dynamic Analysis(IDA),taking the total strain energy and the maximum ratio of elastic strain energy to total strain energy as structural performance indexes,the strain energy time history curve and the vulnerability curve of the dam under the action of the main aftershock sequence are obtained.And then the influence of the main aftershock sequence on the seismic performance of the dam is studied.The results show that the strain energy time history curve under the main aftershock sequence is above the single main earthquake,which indicates that the main aftershock sequence will aggravate the damage degree of the dam body,especially the spectral acceleration of the dam body under the natural vibration period Sa(T1)is large,the damage degree of dam body is more obvious;The vulnerability curve under the action of the main aftershock sequence is above the single main earthquake,indicating that the failure probability of the dam body is higher than that of the single main earthquake;The failure probability of the main aftershock sequence is related to the main earthquake intensity.The higher the main earthquake intensity is,the greater the failure probability of the main aftershock sequence is.