摘要
实际工程的地震危险性概率分析结果表明,即使潜在震源参数和衰减规律等输入参数完全相同,仅因震级积分步长和地震危险性曲线控制点取值不同,就可导致计算结果的显著差异。对于根据衰减规律累加潜源dxdy子源面积计算地震危险性的软件,震级积分步长建议不大于0.05级。危险性曲线控制点的范围应足够大,控制点应该适当增加密度且按对数均匀取值,以保证跨几个数量级的不同周期、不同超越概率反应谱的相对精度。上述积分步长和控制点取值的差异属于主观不确定性,在工程问题的数值计算中普遍存在。此类不确定性影响的敏感性与软件编制的技巧有关,通过减小积分步长、加密控制点可将其影响减小乃至消除。对于特定软件,改变积分步长和控制点密度,对比试算结果,不难确定兼顾计算速度和精度的合理取值。
The results of probabilistic seismic hazard analysis for actual project show that, magnt- tude integral step and seismic hazard curve control points can lead to significant differences in the calculation results, even if whole input parameters are identical, including potential source and attenuation law. For the seismic hazard analysis software that accumulates sub potential source area dxdy according to the attenuation law, magnitude integral step is suggested to be less than 0.05. The range of hazard curve control points should be large enough, the control points should properly increase density with logarithmically uniform values, in order to ensure relative accuracy of response spectra of different periods for different probabilities of exceedance, which are distrib- uted across several orders of magnitude. Above selection of integral step and control points is subjective uncertainty that appears widely in engineering problems with numerical calculation. The influence can be reduced or even eliminated by reducing the integral step, and increasing con- trol point density. Sensitivity of the effects of such uncertainties is related to the skills of soft- ware programming. For specific software, reasonable values, taking both computational speed and accuracy into account, are not difficult to determine by changing the integral step and control point density and comparing the trial results.
出处
《防灾减灾工程学报》
CSCD
北大核心
2016年第5期798-803,共6页
Journal of Disaster Prevention and Mitigation Engineering
基金
中国地震局老专家科研基金课题项目(201409)资助
关键词
地震安全性评价
地震危险性分析
震级积分步长
危险性曲线控制点
主观不确定性
seismic safety evaluation
seismic hazard analysis
magnitude integration step
control point of seismic hazard curve
subjective uncertainty
