摘要
近地表隐伏断层直接影响工程安全施工。通过构建浅覆盖层下方陡立界面断层数值模型,分析近地表隐伏断层地震波场的传播与转换规律。通过工程实测数据验证了数值模拟波场响应特征的可靠性,并利用初至波走时层析成像技术对地下介质波速进行成像。研究结果表明:(1)初至波转换形成的断点绕射波具有频率升高、速度突变的特点,可清晰指示测区内断裂带的存在,可作为现场数据采集时断层的直观反映;(2)工程实测中通过原始波形到时、频率信息可初步判断断层的存在,基于射线追踪的初至波层析成像结果与后期钻孔揭露情况基本吻合,说明初至波层析成像在浅层地震勘探中的实用性;(3)接收测线排列内布设震源的方式,两侧震源延拓距离短,无需额外为震源激发提供场地,在工程施工中具有经济、快速、高效的特点,可作为野外复杂地表条件地下浅层结构探测的有效观测系统使用。
Near-surface buried faults directly affect the safety of engineering construction.This work established a numerical model of steep interface faults under shallow overburden,and analyzed the propagation and transformation law of seismic wave field of near-surface buried faults.The reliability of the numerical simulation of wave field response characteristics was verified by the measured project data,and the tomography technology of the first-break wave travel time was used to image the wave velocity of underground media.The results show that:(1)The diffraction wave of fault points formed by the first-break wave conversion is featured by increasing frequency and sudden velocity changes,which can clearly indicate the existence of the fault zone in the survey area and can be used as an intuitively reflect faults in field data acquisition.(2)In engineering measurements,the existence of faults can be preliminarily judged by the arrival time and frequency information of the original waveform.The first-break wave tomography based on ray tracing is basically consistent with the later drilling exposure,indicating that the first-break wave tomography is practical in shallow seismic exploration.(3)The method of arranging the source in receiving line arrangement has a short extension distance on both sides of the source,and there is no need to provide additional space for the source excitation.It is economic,rapid and efficient in engineering construction,and can be used as an effective observation system for underground shallow structure detection under field complex surface conditions.
作者
孙茂锐
丁昕
石川
李星
陈超
刘路
SUN Maorui;DING Xin;SHI Chuan;LI Xing;CHEN Chao;LIU Lu(Anhui Transport Consulting&Design Institute Co.,Ltd.,Hefei,Anhui 230088;Research and Development Center on Technology and Equipment for Energy Conservation and Environmental Protection of Highway Transport,Hefei,Anhui 230088)
出处
《地质与勘探》
CAS
CSCD
北大核心
2023年第5期1043-1053,共11页
Geology and Exploration
基金
地球内部多尺度成像湖北省重点实验室开放基金项目(编号:SMIL-2017-10)
安徽省交通规划设计研究总院股份有限公司科研项目(编号:HF220191)联合资助。
关键词
隐伏断层
近地表
地震波场
初至波
波场特征
层析成像
buried fault
near surface
seismic wave field
first-break seismic wave
wave field characteristics
tomography
作者简介
第一作者:孙茂锐(1984年-),男,2007年毕业于中国地质大学(武汉),地球物理学专业,获学士学位,高级工程师,现主要从事公路工程物探勘察工作。E-mail:sunmaorui123@163.com;通讯作者:丁昕(1998年-),男,2021年毕业于中国矿业大学,地球探测与信息技术专业,获硕士学位,助理工程师,现主要从事地震波场数值模拟研究与应用。E-mail:1633043607@qq.com。
