利用谱元法研究震源参数对于近断层地震动上盘效应的影响  

Influence of Source Parameters on the Hanging Wall Effect of Near-fault Earthquake Motion by Spectral Element Method

作　　者：万志文 钟菊芳[1] Wan Zhiwen;Zhong Jufang(College of Civil Engineering and Architecture,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学,土木建筑学院,南昌330063

出　　处：《震灾防御技术》2023年第3期450-461,共12页Technology for Earthquake Disaster Prevention

基　　金：国家自然科学基金项目(51969019、51468045);2022年度水利部重大科技项目(SKS-2022100);中国水利水电科学研究院基本科研业务费专项项目(EB110145 B0012021);南昌航空大学研究生创新专项资金立项项目(YC2021-112)。

摘　　要：国内外已有诸多学者基于强震记录或数值模拟方法开展了近断层地震动的上盘效应分析,并获得了初步的认识,但上盘效应随震源参数的变化规律仍有待深入探讨。本文使用运动学有限断层震源模型,运用高精度谱元法模拟逆断层破裂模式下近断层区域地震动,对比上、下盘地震动差异进而分析近断层地震动上盘效应。通过改变单一震源参数,研究断层上界埋深、震级大小以及断层倾角对地震动上盘效应的影响规律。研究结果表明:(1)使用运动学有限断层震源的谱元法数值模拟可以较好地反映近断层上盘效应;(2)上盘效应随测点到断层上界在地表投影的水平距离Rx的增加先增大后减小,最终趋于稳定。(3)上盘效应随断层上界埋深的增加先增大后减小,且随着断层上界埋深的增加,上盘效应峰值区会向远离断层破裂迹线的方向扩展。(4)上盘效应受矩震级影响较小,但总体随矩震级的增大而增大;上盘效应峰值区到断层破裂迹线的距离不随矩震级的变化而变化。(5)随着断层倾角的增加,上盘效应先增大后减小,当断层倾角为45°时上盘效应最为明显;随着断层倾角增加,上盘效应峰值区会向远离断层破裂迹线的方向扩展;当断层倾角为90°时不存在上盘效应。Several researchers domestically and internationally have studied the hanging wall effect of near-fault ground motion using strong earthquake record or numerical simulation approach and have made preliminary knowledge.However,the variation law of hanging wall effect with source parameters is still unclear and requires more discussion.In this paper,the kinematic finite fault source model is used to simulate the ground motion in the near-fault region under the reverse fault rupture mode with the high-precision spectral element method.The difference of ground motions between the hanging wall and footwall is compared to analyze the hanging wall effect of near-fault ground motion.Then,by adjusting the single source parameters,the impact of the buried depth of the upper boundary of the fault,magnitude,and fault dip on the hanging wall effect of ground motion is investigated.The result demonstrates that:(1)Numerical simulation using the spectral element method with kinematic finite fault source reflects the near-fault hanging wall effect well;(2)The hanging wall effect increases first,then decreases,and finally tends to be stable with the improve of the horizontal distance Rx from the measuring point to the upper bound of the fault.(3)The hanging wall effect climbs up and then declines with the rise of buried depth of upper boundary of fault;and the peak area of the he hanging wall effect will expand in the direction far from the fault rupture trace.(4)The hanging wall effect is less affected by moment magnitude but enlarges with the increase of moment magnitude.The distance from the peak area of hanging wall effect to the fault rupture trace does not change with the change of moment magnitude.(5)With the increase of fault dip,the hanging wall effect growths first and then decays,the hanging wall effect is the most obvious when the fault dip angle is 45°,and the peak area of hanging wall effect will appear far away from the fault rupture trace.There is no hanging wall effect when the fault dip is 90°.

关 键 词：近断层地震动 上盘效应 谱元法 地震动模拟 运动学有限断层震源 震源参数 

分 类 号：TU435[建筑科学—岩土工程]