基于盾构隧道管片注浆模拟平台的地质雷达试验与应用

GPR test and application based on shield tunnel segment grouting simulation platform

基于富水圆砾层地质条件下全断面、全尺寸盾构隧道管片壁后注浆模拟试验平台,研究测试了管片、注浆层、富水圆砾层的电性参数,首次发现管片壁的雷达波多次反射信号与注浆层反射信号重叠问题,严重影响目标信号的判译。通过电磁波理论计算和试验,对雷达探测系统的参数进行优化,如采样间距、采样时窗、天线频率和电磁极化率,特别是天线收发距的改进优化等,有效解决这一关键问题。试验成果在南宁轨道交通2号线的实际工程应用,取得令人满意的效果,也为今后地质雷达探测应用提供实践经验的参考和借鉴。

Based on the grouting simulation test platform behind the segment wall of the full section and full size shield tunnel under the geological condition of the water rich pebble layer,the electrical parameters of the segment,grouting layer and water rich pebble layer are studied and tested.It is found for the first time that there is the overlap problem for the multiple reflected signals of the segment wall radar wave and the reflected signals of the grouting layer,which seriously affects the interpretation of target signals.Through theoretical calculation and test of electromagnetic wave,the parameters of radar detection system are optimized,such as sampling interval,sampling time window,antenna frequency and electromagnetic susceptibility,especially the improvement and optimization of antenna transceiver distance,the key problem can be effectively solved.The experimental result has been applied to Nanning Rail Transit Line No.2 in practical engineering project and satisfactory result is achieved.It also provides the practical experience and reference for the future application of geological radar detection.