基于地震动随机合成的地震风险曲线研究

发布时间：2018-08-20 16:41

【摘要】：交通网络的震后通行性能对于震后救援及重建具有重要意义,而交通网络中.的桥梁结构易损性是影响交通网络整体连通可靠度的关键因素。概率地震危险性分析可为桥梁结构易损性分析提供必须的地震风险曲线及地震动参数。将概率地震危险性分析与地震学领域震源-传播途径-场地条件一体化的地震动模拟方法结合起来,计算地震风险曲线及地震动参数,对区域交通路网连通可靠度的研究及路网风险模型的建立,具有较好的学科交叉性和重要的工程意义。本文以四川省某高烈度区交通路网为例,借助有限断层地震动随机合成方法,对路网区域进行了地震动模拟,建立了区域地震动参数预测公式,结合概率地震危险性分析方法,对路网桥梁节点进行了地震危险性评价,给出了各桥梁场址的地震风险曲线。首先,阐述了基于地震动随机合成的概率地震危险性分析的理论方法和技术流程,详细介绍了地震动合成所需参数的物理含义。考虑到参数的不确定性,将一些关键参数视为随机变量,在地震动合成时随机生成其参数值。以四川省某高烈度区交通路网为研究对象,通过区域地质和地震活动性资料,确定了各参数的取值方法和概率分布特征,完成了研究区域内8个方向192个场点处的地震动随机合成;在此基础上,利用Robust回归得到了研究区域内PGA和不同周期PSA的地震动预测公式,并与现有的四川及邻近地区的典型地震动预测公式进行了对比;最后,基于回归的地震动预测公式,结合概率地震危险性分析,对目标交通路网的40个桥梁节点进行了地震危险性分析,得到各个桥梁场址的风险曲线,与基于传统地震动预测公式得到的地震风险曲线进行了对比,并探讨了基于本文风险曲线得到的地震动设计参数与基于传统风险曲线得到的地震动设计参数差异,以及对不同区域桥梁节点易损性和路网整体连通可靠度的影响。
[Abstract]:The traffic performance of traffic network after earthquake is very important to rescue and reconstruction after earthquake. The vulnerability of bridge structure is the key factor to affect the overall connectivity reliability of traffic network. The probabilistic seismic hazard analysis can provide the necessary seismic risk curve and seismic parameters for the vulnerability analysis of bridge structures. Combining the probabilistic seismic hazard analysis with the seismic simulation method which integrates focal propagation path and site conditions in seismology field, the seismic risk curve and seismic parameters are calculated. The research on the connectivity reliability of regional traffic network and the establishment of road network risk model have good interdisciplinary intersections and important engineering significance. Taking a traffic network in a high intensity area of Sichuan Province as an example, the ground motion of a road network area is simulated by means of random synthesis method of limited fault ground motion, and the prediction formula of regional ground motion parameters is established, and the probabilistic seismic hazard analysis method is combined. The seismic risk assessment of bridge nodes in road network is carried out, and the seismic risk curve of each bridge site is given. Firstly, the theoretical method and technical flow of probabilistic seismic hazard analysis based on random synthesis of ground motion are described, and the physical meaning of the parameters required for the synthesis of ground motion is introduced in detail. Considering the uncertainty of the parameters, some key parameters are regarded as random variables, which are randomly generated when the ground motion is synthesized. Taking the traffic network of a high intensity area in Sichuan Province as the research object, the method of choosing the value of each parameter and the characteristics of probability distribution are determined through the regional geological and seismicity data. On the basis of the random synthesis of ground motion at 192 field points in 8 directions in the study area, the prediction formulas of ground motion for PGA and PSA of different periods in the study area are obtained by using Robust regression. And compared with the existing typical earthquake prediction formulas in Sichuan and adjacent areas. Finally, based on the regression prediction formula of ground motion, combined with the probabilistic seismic hazard analysis, Based on the seismic hazard analysis of 40 bridge nodes in the target traffic network, the risk curves of each bridge site are obtained, which are compared with the seismic risk curves obtained from the traditional ground motion prediction formula. The difference between the design parameters of ground motion based on the risk curve and the design parameters of ground motion based on the traditional risk curve is discussed, and the influence on the vulnerability of bridge nodes in different regions and the reliability of the overall connectivity of the road network is also discussed.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55

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