基岩输入时程随机数对场地峰值加速度的影响研究

Effect of Random Numbers of Bedrock Input Time Histories on the PGA from Site Response Analyses

研究基岩输入时程随机数对场地峰值加速度的影响,对核电厂设计地震动参数的合理确定具有重要意义。本文选取了某重要核电站场地具有代表性的3个钻孔,建立了场地计算模型。根据确定性方法、概率性方法得到的基岩反应谱及其包络谱,基于不同随机数,分别合成了400条基岩输入时程。采用LSSRLI-1程序进行了场地地震反应,根据4800个计算结果,研究了不同随机数对地表峰值加速度的影响,给出了自然对数下峰值加速度标准差的估计,揭示了峰值加速度的分布规律,提出了对核电厂设计地震动参数合理确定的建议。

It is important to study the influence of the random numbers of bedrock input time histories on the peak ground acceleration （PGA） from site response, analyses and is of great significance for the determination of design ground motion parameters for nuclear power plants. Three representative boreholes of an nuclear power plant site were selected, and the site calculation models were established. Respectively, according to deterministic methods and probabilistic methods, the bedrock response spectra and the envelope spectra were determined. Based on different random numbers, 400 bedrock input time histories were respectively synthesized. Based on the LSSRLI-1 program, the seismic responses of the sites were studied. According to the results of 4800 calculations, we analyzed the effects of different random numbers on the surface PGA. The estimation of the standard deviation of peak acceleration under natural logarithm was given, and the distribution of PGA was revealed. Suggestions on reasonable determination of design ground motion parameters of nuclear power plant are put forward.