隧道施工期超前预报地质雷达异常干扰识别及处理

Interpretation and Treatment of Interfering Factors in Advance Geological Prediction by Ground Penetrating Radar of Tunnel Construction

受隧道施工复杂环境的影响,地质雷达在超前地质预报中经常遇到各种干扰信号,会对不良地质体探测和预报的准确性造成影响。采用现场实测的方法对隧道地质雷达探测过程中掌子面附近台车等金属物体、探测表面凹凸不平、电缆与输电线路、测线表面金属或非金属干扰物、探测区积水积泥以及底板测线附近金属物体等常见干扰因素进行分析,研究其在雷达处理图像上的表现特征与识别方法,并从相对介电常数取值、直达波拾取、天线移动、测线里程标记、增益调节和数据处理等方面讨论减少或消除干扰因素的措施。研究成果有利于提高地质雷达在隧道超前预报中的准确性,并对类似工程具有一定的参考和借鉴意义。

The ground penetrating radar is usually used to predict tunnel geology. However,it is often disturbed by interfering factors in complex tunnel construction environment; as a result,the prediction accuracy for bad geology can not be guaranteed. Some normal interfering factors,i. e. metal objects around tunnel face,detection surface roughness,cable and transmission line,metal / nonmetal of detection line,water and mud and metal around detection line on tunnel floor,are studied. The expression characteristics on radar image and interpretation of the interfering factors are analyzed. Countermeasures are discussed in terms of relative dielectric constants,direct wave pickup,radar antenna movement,survey line mileage marking,gain control and data processing. The study results can provide reference for similar projects in the future.