近断层地震动场预测——以长春市为例
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摘要
断层带附近地震动场分布的研究,是当前地震工程领域研究的热点问题之一。近断层地震动场的分布对在断层附近进行抗震结构设计时,不仅是提供地震动输入,也是确定建设场地避让范围的重要依据之一。以区域地震构造背景分析、目标断层活动性鉴定、地震危险性评价为基础,结合断层探测结果,利用统计经验关系等最终确定发震断层,并建立相应的震源模型。采用显式有限元和并行计算技术计算目标区域场地的长周期地震动。利用有限断层随机合成的方法,计算高频地震动。将低频和高频地震动合成为目标区域内的宽频带地震动时程。对局部特殊场地条件地区,基于场地调查和勘探的数据,利用等效线性化等方法进行一维土层的非线性反应计算,给出这些特殊场地的宽频带地震动时程。最后,根据地震动时程获得设定地震发生时,目标区域的峰值加速度分布预测图和相应的反应谱。以长春市为例预测了在设定地震发生时,近断层地震动场的分布情况。当长春尖山子—卡伦断层发生6.0级地震时,潜在破坏性地震动的影响范围集中在附近,沿断层走向分布。加速度峰值沿断层垂直变化,主要为90 Gal～140 Gal。只是在长春市南部加速度峰值达到200 Gal。本研究的预测结果具备断层附近地震动的一些最基本的特征,符合当前对断层附近地震动的基本认识。
The study of near fault ground motion field distribution is one of hot points in earthquake engineering.Near-fault ground motion field distribution not only provides an input motion but also provides the range of avoiding belt of the foundation in seismic design.Based on regional geological structure,activity assessment of aimed fault and assessment of seismic hazard,using experience statistical relationship to determine seismogenic faults,the corresponding source model was set up.Combining 3-D finite element analysis and parallel computing,the long period ground motions were calculated.The method of limited-fault random synthesis was used to calculate the high frequency ground motion.The high-frequency and low-frequency ground motions were composed to broad-frequency ground motion.1-D equivalent linearization method was used to calculate the broad-frequency ground motion time histories of some special local sites according to survey data.The PGA distribution and the corresponding response spectra of the target region are got according to the ground motion time histories when the design earthquake occurs.As an example,the near-fault ground motion distribution of Changchun City was predicted when a setting earthquake occurred.When an Ms6.0 earthquake occurs on the Jianshanzi-Kalun fault,the influence range of potentially destructive ground motion is near the fault,and the distribution of influence range is along the fault.The peak acceleration varies along the fault vertically mainly from 90 Gal to 140 Gal and the peak acceleration reaches 200 Gal only in the southern part of Changchun City.The forecasting result has the basic characteristics of near-fault ground motion,and matches the current basic understanding of the ground motion near the fault.
The study of near fault ground motion field distribution is one of hot points in earthquake engineering.Near-fault ground motion field distribution not only provides an input motion but also provides the range of avoiding belt of the foundation in seismic design.Based on regional geological structure,activity assessment of aimed fault and assessment of seismic hazard,using experience statistical relationship to determine seismogenic faults,the corresponding source model was set up.Combining 3-D finite element analysis and parallel computing,the long period ground motions were calculated.The method of limited-fault random synthesis was used to calculate the high frequency ground motion.The high-frequency and low-frequency ground motions were composed to broad-frequency ground motion.1-D equivalent linearization method was used to calculate the broad-frequency ground motion time histories of some special local sites according to survey data.The PGA distribution and the corresponding response spectra of the target region are got according to the ground motion time histories when the design earthquake occurs.As an example,the near-fault ground motion distribution of Changchun City was predicted when a setting earthquake occurred.When an Ms6.0 earthquake occurs on the Jianshanzi-Kalun fault,the influence range of potentially destructive ground motion is near the fault,and the distribution of influence range is along the fault.The peak acceleration varies along the fault vertically mainly from 90 Gal to 140 Gal and the peak acceleration reaches 200 Gal only in the southern part of Changchun City.The forecasting result has the basic characteristics of near-fault ground motion,and matches the current basic understanding of the ground motion near the fault.
引文
[1]刘启方,袁一凡,金星,等.近断层地震动的基本特征[J].地震工程与工程震动,2006,26(1):1-10.LIU Qifang,YUAN Yifan,JIN Xing,et al.Basic Characteristics of near-fault ground motion[J].Journal of Earthquake Engineering and EngineeringVibration,2006,26(1):1-10.(in Chinese)
[2]刘启方.基于运动学和动力学震源模型的近断层地震动研究[D].哈尔滨:中国地震局工程力学研究所,2005.LIU Qifang.Studies on near-fault grond motions based on kinematic and dynamic source models[D].Harbin:Institute of Engineering Mechanics,China Earthquake Adminstation,2005.(in Chinese)
[3]刘启方,丁海平.近断层地震动预测实例[J].地震工程与工程震动,2008,28(6):28-32.LIU Qifang,DING Haiping.An example of near-fault strong ground motion predication[J].Journal of Earthquake Engineering and Engineering Vi-bration,2008,28(6):28-32.(in Chinese)
[4]丁海平,刘启方,黄勇,等.三维地震动场数值模拟并行计算系统[J].地震工程与工程震动,2004,24(2):19-23.DING Haiping,LIU Qifang,HANG Yong,et al.Parallel computer system for 3-D numerical simulation of ground motion[J].Journal of EarthquakeEngineering and Engineering Vibration,2004,24(2):19-23.(in Chinese)
[5]Boore D M.Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra[J].BSSA,1983,73(6):1865-1894.
[6]Irikura K,Kamae K,Dalguer L A.Source model for simulating ground motion during the 1999 Chi-Chi earthquake[J].EEES,2000,2(2):1-14.
[7]刘启方.近断层强地震动预测的一些基本问题讨论[J].世界地震工程,2006,24(3):94-100.LIU Qifang.Discussion of some basic problems on predication of near-fault strong motion[J].World Earthquake Engineering,2006,24(3):94-100.(in Chinese)
[8]甘杨,李凡,李大华.一维土层非线性地震反应分析的解析递推格式法[J].吉林大学学报:地球科学版,2006,35(4):631-635.GAN Yang,LI Fan,LI Dahua.Analytical recursion scheme method of the nonlinear earthquake response analysis of one-dimension soil layer[J].Journal of Jilin University(Earth Science Edition),2006,35(4):631-635.(in Chinese)
[2]刘启方.基于运动学和动力学震源模型的近断层地震动研究[D].哈尔滨:中国地震局工程力学研究所,2005.LIU Qifang.Studies on near-fault grond motions based on kinematic and dynamic source models[D].Harbin:Institute of Engineering Mechanics,China Earthquake Adminstation,2005.(in Chinese)
[3]刘启方,丁海平.近断层地震动预测实例[J].地震工程与工程震动,2008,28(6):28-32.LIU Qifang,DING Haiping.An example of near-fault strong ground motion predication[J].Journal of Earthquake Engineering and Engineering Vi-bration,2008,28(6):28-32.(in Chinese)
[4]丁海平,刘启方,黄勇,等.三维地震动场数值模拟并行计算系统[J].地震工程与工程震动,2004,24(2):19-23.DING Haiping,LIU Qifang,HANG Yong,et al.Parallel computer system for 3-D numerical simulation of ground motion[J].Journal of EarthquakeEngineering and Engineering Vibration,2004,24(2):19-23.(in Chinese)
[5]Boore D M.Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra[J].BSSA,1983,73(6):1865-1894.
[6]Irikura K,Kamae K,Dalguer L A.Source model for simulating ground motion during the 1999 Chi-Chi earthquake[J].EEES,2000,2(2):1-14.
[7]刘启方.近断层强地震动预测的一些基本问题讨论[J].世界地震工程,2006,24(3):94-100.LIU Qifang.Discussion of some basic problems on predication of near-fault strong motion[J].World Earthquake Engineering,2006,24(3):94-100.(in Chinese)
[8]甘杨,李凡,李大华.一维土层非线性地震反应分析的解析递推格式法[J].吉林大学学报:地球科学版,2006,35(4):631-635.GAN Yang,LI Fan,LI Dahua.Analytical recursion scheme method of the nonlinear earthquake response analysis of one-dimension soil layer[J].Journal of Jilin University(Earth Science Edition),2006,35(4):631-635.(in Chinese)
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