地铁隧道管片背后隐蔽缺陷无损检测实验平台设计

An Multi-Functional Experimental Platform for the Detection of Hidden Defects Behind Subway Tunnel Segments

为研究电磁波在地铁隧道衬砌结构中的传播和散射规律,设计了一种用于模拟地铁隧道管片背后缺陷检测的实验平台。平台主要由2块足尺盾构隧道标准块、2根不同材质的地下管线和不同尺寸的隐蔽缺陷组成,衬砌背后岩土体用石英砂填充。利用不同频率的探地雷达天线对地铁隧道背后隐蔽缺陷进行探测,可分析管片内部的双层钢筋网对背后不同间距缺陷雷达信号的屏蔽效应,以及不同尺寸缺陷或含水缺陷的典型雷达图像特征。此外,该平台还可以拓展应用于地下管线的探测等地下工程实验教学。

This paper establishes a multi-functional experimental platform designed for detection void behind shield tunnel segments.The purpose is to investigate the GPR responses from the concealed voids behind a shield tunnel.The platform consists two shield tunnel segments,a PVC pipeline,a concrete pipeline,and voids with different sizes buried in quartz sands behind the shield tunnel.Hidden defects behind the shield segments are detected using GPR antennas with different frequencies.A series of laboratory experiments are conducted to analyze and characterize the radar responses of voids.It can analyze the shielding effect of the double-layer rebar mesh inside the shield segment on the hidden defects with different spacing,as well as the response characteristics of GPR B-scan images in different voids.Moreover,the platform has potential for use in underground pipeline experiments in teaching.