摘要
地下空洞给交通出行、工程建设带来了极大的安全隐患。探地雷达作为一种无损探测技术,通过采集和分析电磁波反射信号,可探测地下空洞的位置、尺寸和介质特性等,进而为工程地质勘察和结构无损检测提供重要信息。该文将地下含水及不含水空洞用时域有限差分法进行仿真实验,得到了雷达剖面图及单道波形对比结果,并分析了反射信号的时频特征差异。由于电磁波在水中传播时的衰减,含水空洞下界面反射信号的瞬时频率会出现明显向下偏移,时频分析方法能够为识别地下空洞是否含水提供参考依据。将时频分析方法应用于城市道路空洞的雷达实测数据的处理与分析,结果表明,时频分析方法能够准确判定地下空洞的尺寸及是否含水。
The underground cavity brings great potential safety hazards to traffic and engineering construction.As a kind of non-destructive detection technology,the GPR can detect the location,size and medium characteristics of underground cavity by collecting and analyzing the reflected signals of electromagnetic wave,thus providing important information for engineering geological investigation and structural non-destructive detection.In this paper,the finite difference time-domain(FDTD)method is used to simulate the underground water bearing and non water bearing cavities.The radar profile and single channel waveform comparison results are obtained,and the difference of time-frequency characteristics of reflected signals is analyzed.Due to the attenuation of electromagnetic wave in water,the instantaneous frequency of lower interface reflection signal under water bearing cavity will shift down obviously.The time-frequency analysis method can provide a reference for identifying whether the underground cavity has water or not.The time-frequency analysis method is applied to the processing and analysing of radar measured data of urban road voids.The results show that the time-frequency analysis method can accurately determine the size and whether water having or not of underground cavity.
作者
于建
刘海
李丰果
蒋登学
Yu Jian;Liu Hai;Li Fengguo;Jiang Dengxue(School of Civil Engineering,Guangzhou University;China Railway Tunnel Group Sanchu Co.,Ltd.)
出处
《勘察科学技术》
2020年第2期22-25,42,共5页
Site Investigation Science and Technology
基金
广州市教育局高校产学研结合项目(201831804)
广州建筑产业研究院有限公司科技进步资金资助
关键词
探地雷达
空洞探测
时频分析
ground penetrating radar(GPR)
cavity detection
time-frequency analysis
