CAJ | 학술논문

地震反应分析中的输入界面是一种规定的假想基岩面,其选取具有很大的不确定性,对确定地震动参数的影响很大.本文以北京地区存在剪切波速较高的卵石硬夹层场地为研究对象,探讨实际工程场地中能否将硬夹层选作地震动输入界面的问题.利用一维等效线性化波动方法,对390个含有剪切波速高于500m/s的卵石层场地模型进行地震反应分析计算,讨论卵石层的上覆土层、下伏土层以及卵石层自身特性对地震反应分析结果的影响.计算结果显示,厚度5m左右、剪切波速小于600m/s的卵石层作为地震动输入界面是否合理,主要取决于上覆土层和下伏土层,而卵石层厚度和剪切波速的影响很小.对于一般性工程,当上覆土层厚度大于15m,下伏土层厚度在10m以内时,选取硬夹层顶面与选取钻探揭示的基岩或剪切波速不小于500m/s的土体顶面为输入界面,计算结果差别不大;当上覆土层厚度达到60m,下伏土层的变化对计算结果影响很小.研究表明,在钻探没有揭示出基岩或坚硬土体时,埋深大于60m的硬夹层可以选为地震动输入界面,这一结论对实际的地震安全性评价工作具有一定参考价值.
지진반응분석중적수입계면시일충규정적가상기암면,기선취구유흔대적불학정성,대학정지진동삼수적영향흔대.본문이북경지구존재전절파속교고적란석경협층장지위연구대상,탐토실제공정장지중능부장경협층선작지진동수입계면적문제.이용일유등효선성화파동방법,대390개함유전절파속고우500m/s적란석층장지모형진행지진반응분석계산,토론란석층적상복토층、하복토층이급란석층자신특성대지진반응분석결과적영향.계산결과현시,후도5m좌우、전절파속소우600m/s적란석층작위지진동수입계면시부합리,주요취결우상복토층화하복토층,이란석층후도화전절파속적영향흔소.대우일반성공정,당상복토층후도대우15m,하복토층후도재10m이내시,선취경협층정면여선취찬탐게시적기암혹전절파속불소우500m/s적토체정면위수입계면,계산결과차별불대;당상복토층후도체도60m,하복토층적변화대계산결과영향흔소.연구표명,재찬탐몰유게시출기암혹견경토체시,매심대우60m적경협층가이선위지진동수입계면,저일결론대실제적지진안전성평개공작구유일정삼고개치.
Inputting interface in seismic-response calculation is a required imaginary bedrock surface. The choice of different seismic inputting interfaces has a great influence on the ground motion parameters. In this paper, we will use the cobble layer with high shear wave velocity in the Beijing area to discuss whether the hard layer can be used as inputting interface in practical engineering, 1-D equivalent linear wave methodology is adopted for the seismic-response calculation on 390 engineering site soil profiles which includes some cobble layers with shear wave velocity more than 500m/s. The result shows that overlaying soil and underlying ground of cobble layer play an important role in choosing sort of cobble layer with around 5 m thick and less than 600m/s as reasonable inputting interface; thickness of cobble layer and wave velocity, on the other hand, play minor roles. For general buildings, when the overlaying soil is more than 15m thick and the underlying ground is less than 10m thick, there is no significant difference in calculation results when choosing hard layers or bedrock as inputting interface. In addition, variation of underlying ground's thickness has less effect on calculation when the thickness of overlaying soil reaches more than 60m. Therefore, hard soil layers buried in 60 m or more in depth could be used as the inputting interface in the absence of information about bedrock.