摘要
城市供水钢管脱节检测是当今非开挖工程管道修复与更换的重要任务,探地雷达广泛用于识别供水钢管脱节的位置,为确定探地雷达在供水钢管脱节实际探测中的成像特征,通过gprMax对供水钢管脱节进行了三维正演研究。本文首先根据管道的不同脱节程度建立了三维模型,考虑到土体渗透系数的差异,在供水钢管脱节处建立三维不规则模型用以代表土体浸润区。然后设计测线分布,分别设计垂直于供水钢管走向的测线与沿供水钢管走向的测线用以确定管道位置及脱节位置。最后通过gprMax对模型进行正演模拟。研究结果表明,垂直供水钢管走向测线中,浸润区反射波形同相轴呈现类似双曲线特征,但局部存在错动或中断。沿供水钢管走向测线中,管道未脱节区反射波形同相轴近水平。对于严重脱节与重度脱节管道脱节区反射波形同相轴出现明显错断,可根据错断距离判断脱节距离。对于中度脱节与轻度脱节管道脱节区反射波形同相轴无明显错断,浸润区处管道反射波振幅不稳定,可根据浸润区位置判断脱节位置。本文采用三维模型进行正演研究,对探地雷达探测供水管道脱节的图像解译工作具有指导意义。
The detection of disconnection urban water supply steel pipes is an essential task in current trenchless engineering for pipeline replacement and renovation.Ground-penetrating radar is extensively used to identify the locations of such disconnection pipes.To ascertain the imaging characteristics of GPR in actual detection of disconnection water supply steel pipes,a three-dimensional forward modeling study of them was conducted using gprMax.In this paper,three-dimensional models were initially established based on different degrees of disconnection of the pipeline.Considering the variations in soil permeability coefficient,a three-dimensional irregular model was set up at the disconnection part of water supply steel pipe to represent the soil infiltration zone.Subsequently,the distribution of measurement lines was designed.Measurement lines perpendicular to and along the direction of the water supply steel pipe were respectively designed to determine the pipeline location and the disconnection location.Finally,forward modeling was executed on the model through gprMax.The research results indicate that in the measurement lines perpendicular to the pipe,the reflection waveform event of the infiltration zone shows a hyperbolic-like feature,but with local displacements or interruptions,and the measurement lines along the pipe,the reflection waveform event of the non-disconnection area of pipeline is nearly horizontal.For severely and extremely disconnection pipelines,distinct offsets occur in the reflection waveform event of the disjointed area,and the disconnection distance can be judged based on the offset distance.For moderately and slightly disconnection pipelines,there is no obvious offset in the reflection waveform event of the disjointed area,and the amplitude of the pipeline reflection wave at the infiltration zone is unstable.The disconnection location can be determined based on the position of the infiltration zone.The three-dimensional model for forward modeling research in this paper has which guiding significance for the image interpretation of GPR in the detection of disconnection water supply pipelines.
作者
刘桓宇
易林果
霍宇翔
李远
LIU Huanyu;YI Linguo;HUO Yuxiang;LI Yuan(College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Geological Disaster Prevention and Geological Environmental Protection,Chengdu 610059,China;Chongqing Gaoxin Engineering Investigation and Design Institute Co.,Ltd,Chongqing 401120,China)
出处
《地质装备》
2024年第S01期92-100,共9页
Equipment for Geotechnical Engineering
基金
地质灾害防治与地质环境保护国家重点实验室自主研究课题(编号:SKLGP2023Z018)。
关键词
探地雷达
三维正演
有限差分
管道脱节
ground penetrating radar
3D forward simulation
finite difference
pipes disconnection
