广西覆盖型岩溶区Ⅱ类场地地震效应分析  

Seismic Effect of Type Ⅱ Site in Overlaying Karst Area of Guangxi

作　　者：张忠利 齐文浩[3] 袁媛 罗云 

机构地区：[1]广西壮族自治区地震局,南宁530022 [2]广西工程防震研究院,南宁530022 [3]中国地震局工程力学研究所,哈尔滨150080

出　　处：《震灾防御技术》2015年第3期512-521,共10页Technology for Earthquake Disaster Prevention

基　　金：广西科学研究与技术开发计划项目(桂科攻12426001-5)资助

摘　　要：针对广西特殊的覆盖型岩溶区的场地地质条件,通过收集区内的393个地震工程地质钻孔,利用大量的剪切波速及土工测试资料,建立了土层地震动反应分析模型,采用一维波动的等效线性化方法,对Ⅱ1、Ⅱ2和Ⅱ3三个亚类分别计算得到了地表峰值加速度及相关反应谱,并拟合得到了规准化反应谱,定量分析了广西覆盖型岩溶区Ⅱ类场地地震动的效应。结果表明,三个亚类场地动力放大系数均较大,场地对反应谱平台值的放大作用与对峰值的放大作用并不一致;Ⅱ1、Ⅱ2和Ⅱ3峰值加速度放大倍数分别为1.17、1.31、1.26,而平台值的放大倍数分别为1.49、1.52、1.38;反应谱特征周期分别为0.26s、0.33s和0.39s,反应谱下降段受控于输入反应谱下降段;同时给出了场地反应谱平台值、特征周期和衰减系数的推荐值。上述结果可为确定广西覆盖型岩溶区设计地震动参数提供参考。According to the geological conditions of the Guangxi special karst area, we collected 393 earthquake engineering geological drilling in the region, and established regional seismic dynamic model by using shear wave velocity and soil test data. The peak ground acceleration and response spectrum under site condition sub type Ⅱ 1,Ⅱ2 and Ⅱ3 were calculated by using one-dimensional equivalent linear method of soil seismic response on the wave motion mode. By fitting the normalized response spectrum, we analyzed the effect of Guangxi covered karst area of ground motion. The results indicate that dynamic amplification coefficients of sub type Ⅱ 1, Ⅱ 2 and Ⅱ 3sites are relatively high, amplification effect on flat section value of response spectrum and the peak ground acceleration are not consistent, the peak ground acceleration magnification is respectively 1.17, 1.31, 1.27, but the flat section value of response spectrum magnification is respectively 1.49, 1.52, 1.38. The characteristic period of response spectrum is respectively 0.26 s, 0.33 s, 0.39 s. The descending segment of response spectrum is basically not affected. At the same time, the recommended values of the flat section value, the characteristic period and the attenuation coefficient of response spectrum are obtained. Our results can be used to provide reference for the determination of design ground motion parameters in overlaying karst area of Guangxi.

关 键 词：覆盖型岩溶区 Ⅱ类场地 地震效应 反应谱 

分 类 号：P315.9[天文地球—地震学]