SH波入射下阶跃基岩覆盖土层场地地面运动特征分析  

Characteristic Analysis of Ground Motions of Step Bedrock Site under SH Seismic Waves

作　　者：王加锐 李鸿晶[1] 孙广俊[1] WANG Jiarui;LI Hongjing;SUN Guangjun(College of Civil Engineering, Nanjing Tech University, Nanjing 211816, China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816

出　　处：《防灾减灾工程学报》2017年第5期712-717,共6页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(51278245);国家自然科学基金项目(51308293)资助

摘　　要：利用二维显式有限元场地地震反应分析程序,把不同频谱特性的地震动作为输入基岩的SH波,探讨了阶跃基岩覆盖土层场地地震动空间分布特征,重点研究了覆盖土层厚度和土层性状对场地地表加速度峰值和反应谱的影响。研究表明:对于阶跃基岩覆盖土层场地,覆盖土层厚度变化对相应区域地表地震反应有较为明显的影响,对土层厚度不变区域的地表地震反应影响不明显。土层性状对阶跃基岩覆盖土层场地地表的加速度峰值和反应谱均有重要的影响。软土和上软土下硬土组合土层场地地表的加速度峰值要比硬土场地地表上的大。软土场地中反应谱的峰值要比硬土场地中反应谱的峰值大,硬土场地反应谱峰值对应的周期较短,软土场地反应谱峰值对应的周期较长。土层性状对地震动反应谱的影响,主要体现在短周期分量上。This article studies the impact of soil thickness and soil conditions on the peak ground acceleration and response spectrum of ground motion of step bedrock site by using two-dimensional seismic response analysis program of explicit finite element method.The distribution characteristics of ground motions are summarized.The SH wave is taken from recorded seismic waves of different frequency spectra.Research results are shown as follows：For the step bedrock field,the change of soil layer thickness has a more significant impact on the surface seismic response of the corresponding region and the surface seismic response of soil layer thickness constant region is not obvious.The soil conditions have an important impact on both PGA and response spectra.The peak acceleration of ground surface in soft soil and composite soil layer is greater than that of hard soil.The peak value of the response spectrum in soft soil site is greater than that of the response spectrum in the hard soil site,The peak response spectra period in hard soil is shorter,the peak response spectra period in soft soil is longer.The effect of soil properties on the response spectrum of ground motion is mainly reflected in the short period.

关 键 词：地震波 阶跃基岩覆盖土层场地 土层厚度 土层性状 地震动 

分 类 号：P315.9[天文地球—地震学]