复合谱加速度在概率地震危险性分析及地震动记录选取的应用

THE APPLICATION OF COMPOUND SPECTRAL ACCELERATION IN PROBABILISTIC SEISMIC HAZARD ANALYSIS AND IN SELECTION OF GROUND MOTION RECORDS

  • 摘要: 采用偏最小二乘回归原理构造考虑多个周期影响的复合谱加速度,以西安地区为研究对象,给出复合谱加速度的地震动预测模型,基于蒙特卡洛模拟得到复合谱加速度的概率地震危险性分析。在此基础上进行概率地震危险性分解,根据加权方法确定基本自振周期分别为0.2 s、1.0 s、3.0 s的设定地震,提出基于复合谱加速度的目标反应谱,并且根据贪心优化算法进行地震动记录选取。结果表明:考虑多个周期影响的复合谱加速度危险性曲线是3个典型周期危险性曲线不同权重比累加的结果,相比于单一谱加速度而言,复合谱加速度的危险性曲线可以综合地评估概率地震危险性,经过条件谱和贪心优化算法挑选出的地震动记录谱加速度中位值、对数标准差与条件均值谱匹配较好,所选地震动反应谱均在条件均值谱2.5%和97.5%分位值范围内。

     

    Abstract: A partial least squares regression principle is employed to construct a compound spectral acceleration that accounts for the effects of multiple vibration periods. Taking the Xi’an region as research subject, a ground motion prediction model for the compound spectral acceleration is developed. The probabilistic seismic hazard analysis for the compound spectral acceleration is performed using Monte Carlo simulation. Based on the deaggregation of probabilistic seismic hazard, scenario earthquakes for fundamental natural vibration periods of 0.2 s, 1.0 s, and 3.0 s are determined using the weighted method. A target response spectrum based on the compound spectral acceleration is proposed, and the ground motion records are selected using a greedy optimization algorithm. The results show that the hazard curve of the compound spectral acceleration represents the summation of hazard curves from three typical periods with different weighting ratios, providing a comprehensive assessment of probabilistic seismic hazard, compared to single spectral acceleration. The median values and logarithmic standard deviations of spectral accelerations from the selection of ground motion records through the conditional spectrum and greedy optimization algorithm show a good agreement with the conditional mean spectrum, and the selected ground motion response spectra all fall within the 2.5% and 97.5% percentiles of the conditional mean spectra.

     

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