岩溶区土洞对自由场地震动放大效应的影响  

INFLUENCE OF SOIL CAVE IN KARST AREA ON GROUND MOTION AMPLIFICATION EFFECT OF FREE SITE

作　　者：兰景岩[1,2] 史庆旗 刘娟 邬俊杰 LAN Jingyan;SHI Qingqi;LIU Juan;WU Junjie(Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of Green Building Materials and Construction Industrialization,Guilin University of Technology,Guilin 541004,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)

机构地区：[1]桂林理工大学,广西岩土力学与工程重点实验室,桂林541004 [2]桂林理工大学,广西绿色建材与建筑工业化重点实验室,桂林541004 [3]中国地震局工程力学研究所,地震工程与工程振动重点实验室,哈尔滨150080 [4]地震灾害防治应急管理部重点实验室,哈尔滨150080

出　　处：《工程地质学报》2024年第5期1771-1778,共8页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:52168067);广西自然科学基金项目(资助号:2021GXNSFAA220017);广西高等学校千名中青年骨干教师培育计划项目(2020)。

摘　　要：岩溶区土洞的发育改变了自由场的地震工程地质条件,从而影响了地表地震动力响应结果。为探讨岩溶区土洞对地震动场地效应的影响,设计并构建典型岩溶区土洞自由场地,利用有限差分法开展了不同地震动输入条件下的含土洞场地的地震反应分析。通过与自由场地震反应分析结果对比可知:(1)土洞的存在阻碍了地震波的传播,从而使得地表中心点峰值加速度显著减小,随着输入地震动峰值增大,土洞的影响范围增大,土洞附近地表峰值加速度呈现出先增大后减小,最后逐渐趋向于自由场;(2)土洞的存在使场地的竖向位移增大,且随输入加速度峰值增大而增大、对水平向峰值位移影响较小;(3)加速度放大系数总体呈现出先增大后减小的趋势,随输入加速度峰值增大而减小;(4)土洞的存在使得反应谱的短周期幅值减小,这种减小幅度受输入地震动峰值的影响不明显。The seismic engineering geological conditions of the free field can be changed by soil caves in Karst areas,which affects the results of surface seismic dynamic response.To study the influence of soil caves on ground motion amplification in Karst areas,we used the finite difference method to analyze the seismic response of the site with soil caves under different ground motion input conditions.In this paper,we have several important conclusions as follows:(1)Because the propagation of seismic waves is blocked by soil caves,the peak acceleration at the center of the ground surface is reduced significantly.With the increase of the input ground motion peak,the influence range of the soil caves increases,and the peak acceleration near the soil caves first increases and then decreases,eventually tending toward the free field trend.(2)The vertical displacement of the site is increased by the presence of soil caves.With the increase of peak acceleration input,the vertical displacement also increases gradually.The soil caves have little influence on the horizontal peak displacement.(3)The acceleration amplification coefficient increases first and then decreases,and decreases with the increase of the peak acceleration input.(4)The value of the response spectrum short period is decreased by the presence of soil caves.This reduction is not significantly affected by the peak acceleration input.

关 键 词：岩溶区土洞 有限差分法 地震动场地效应 峰值加速度及反应谱 

分 类 号：P315.9[天文地球—地震学] TU449[天文地球—固体地球物理学]