金属管线对探地雷达探测道路地下病害的干扰

The study of the interference region around metal pipeline in underground disease detection of urban road

探地雷达作为一种电磁波反射类的方法,在城市道路地下病害探测中受金属管线干扰较大。为分析地下病害位于金属管线的不同部位的干扰问题,从探地雷达的分辨能力出发,推导出金属管线侧方探测干扰区的基本计算公式,结合正演数值模拟和实际同等规模建设的物理模型,对金属管线周边干扰区进行了验证试验。结果表明:金属管线两侧一定跨度范围内,存在一垂直高度为一个电磁波波长的干扰区,当地下病害位于该区域时,其反射波组受干扰,不利于病害属性和规模的解释,而当地下病害位于金属管线的正下方时,其不能被目前常用的单体式天线探测到。

As a geophysical method based on the reflection of electromagnetic wave,ground penetrating radar（ GPR） is interfered by the underground metal pipeline in underground disease detection of urban road. In order to find out the interference region around the metal pipeline,the authors deduced the calculating formula of the interference region based on the resolution of GPR. After the numerical simulation and the physical model simulation,the authors found that there is an interference region with a vertical height of the electromagnetic wave length beside the metal pipeline. When the underground disease is located in this region,its reflection wave group will be disturbed,which is not conducive to the interpretation of disease＇s attribute and scale. And when the underground disease is located under the metal pipeline,it cannot be detected by the current single type antenna.