探地雷达在盾构前向探测应用中工作参数的选择

Working parameters selection for ground penetrating radars during frontal-detection shielded tunneling

为了实现利用探地雷达对盾构前向地质做出超前预报,规避盾构施工风险,选取适当的探地雷达中心频率及地质数据采集参数,对提高数据的可靠性和有效性极为重要.结合盾构施工要求,分析了探地雷达天线中心频率选择的主要影响因素,指出天线中心频率的选择既要满足对探测深度和分辨率的要求,又要满足其在盾构机上的安装情况.总结了探地雷达在盾构前向探测超前预报应用中地质数据采集参数设置的一些基本原则与技巧,分析了A/D采样位数、采集点数和扫描速率三者之间的关系.

In order to precautiously forecast frontal geological conditions using Ground Penetrating Radar （GPR） and thereafter avoid construction risks during shielded tunneling,it is extremely critical to select proper central frequency and geological data gathering parameters of GPRs so as to improve data reliability and feasibility.To meet shielded construction requirements,the major impacts on central frequency selection for GPR antennas are analyzed.For this purpose,the central frequency selection should satisfy the demands on not only detection depth and resolution,but also the installation onto shielded tunneling machines.In so doing,the basic principles and skills are summarized on the parameter setting for geological data gathering during precautious forecasting.In addition,the correlations among A/D sampling bites,number of sampling points and scanning speeds are pinpointed.