摘要
对于受多条发震构造影响的大坝场址,合理估计坝址地震动输入是实现近场地震作用下不溃坝目标的前提条件。文章主要目标是对地震地质环境复杂的场址建立适合于工程应用的地震动参数评价方法。首先对随机有限断层法模拟近场大震的适用性进行分析,结果表明该方法不仅可以描述断层破裂源,考虑地震波路径、场地衰减等因素,而且计算效率高,能够解决地震动模拟中复杂震源设置与计算效率的问题,可用于大坝场址地震动参数估计;然后基于对随机有限断层法参数的不确定性分析,建立一套能够考虑多个发震构造对坝址影响的地震动参数综合评价体系,包括设置震源、路径及场地条件参数的取值范围及水平、设计多方案(多权重)地震动模拟方案、各参数取值的权重系数计算原则与方法;最后获得能够表征不同地震危险性的参数估计方法。该文建立的方法能够考虑坝址发震构造的复杂性,给出多层次、多风险水平的评价结果,为近场大震作用下大坝抗震安全评价提供合理的地震动参数。
For dam sites affected by multiple seismogenic tectonics, providing reasonable estimation of ground motion input is the prerequisite to achieve the goal to prevent collapse of high dam under near-field earthquake.The purpose of this study is to establish a method for determining near-field ground motion parameters suitable for engineering applications for sites with complex seismic and geological environment.Firstly, the applicability of stochastic finite fault method in near-field large earthquake simulation is analyzed.The results show that this method can not only describe the fault rupture of the real situation but also can consider the attenuation of seismic wave path and site with high computational efficiency.This method solves the problem of matching the complex source parameters with the computational efficiency in seismic simulation, and thus can be applied estimate the seismic parameters of dam site.Secondly, based on the parameters uncertainty analysis of the stochastic finite fault method, a comprehensive evaluation system of ground motion parameters is established, considering the influence of different seismogenic tectonics on the dam site.The new evaluation system includes the setting range and level of parameters for source, path and site condition, the design of multi-scheme(multi-weight)ground motion simulation scheme, and the calculation principles and methods for determining the weight coefficients of each parameter.Finally, a parameter estimation method characterizing different seismic hazards is obtained.By the method proposed in this paper, the complexity of the seismogenic tectonics near the dam site can be taken into account, the evaluation results with multi-level and multi-risklevel can be given, and reasonable ground motion for the seismic safety evaluation of the dam under near-field earthquake can be provided.
作者
俞瑞芳
时洪涛
孙吉泽
张冬锋
俞言祥
Yu Ruifang;Shi Hongtao;Sun Jize;Zhang Dongfeng;Yu Yanxiang(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;China Three Gorges Projects Development Co.,Ltd.,Chengdu 610000,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2020年第7期1-11,27,共12页
China Civil Engineering Journal
基金
国家重点研发计划(2017YFC0404901)
中国长江三峡集团公司科研项目(XLD/2115)。
关键词
随机有限断层法
地震动模拟
地震危险性
参数不确定性
stochastic finite fault method
simulation of ground motion
seismic hazard
parameter uncertainty
