地震动持时对核岛结构设计地基场地非线性地震响应影响分析

INFLUENCE ANALYSIS OF GROUND MOTION DURATION ON NONLINEAR SEISMIC RESPONSE OF NUCLEAR ISLAND DESIGN FOUNDATION

选取AP1000核岛结构标准设计地基的5种场地参数,开展了场地非线性地震反应的计算分析。计算分析中,以不同的地震动输入界面作为计算基底,并分别以不同持时的人工地震动加速度时程作为输入地震动。计算结果显示:对于硬岩和软岩场地,计算基底输入地震动持时对场地地表峰值加速度和加速度反应谱的影响可忽略不计;对于土层场地,长持时输入地震动的场地地表峰值加速度和高频段的(约大于10 Hz)加速度反应谱明显大于短持时的计算结果,考虑到地震动持时也可能对非基岩核电厂抗震设防产生一定影响,进一步开展研究十分必要。

5 site models coressonding to the standand design foundation of AP1000 nuclear island were adopted to calculate and analyze the nonlinear site effect on design ground motion. In the calculation,different rock interfaces were considered as the input seismic wave,and two acceleration time-histories with same response spectra and different durations were selected as the input seismic wave. The analysis results showed that： the effect of input seismic wave duration was weak and could be neglected on the peak acceleration and acceleration response spectrum of the ground motion for the hard rock site and soft rock site; however for soil sites,the peak acceleration and acceleration response spectrum in high frequency range（ 10 Hz） of the ground motion were clearly greater in the case of acceleration time-history with long duration than those in the case of acceleration time-history with short duration. In consideration of the impact of the ground motion on the aseismic design of nuclear power plant,the further research would be necessary to realize the effects of the duration of acceleration time-histroy on design ground motion of nuclear island site.