探地雷达探测地下目标时的波速估计

Estimation of EM wave velocity in detecting underground target by GPR

在利用探地雷达(GPR)进行工程检测过程中,电磁波在地下介质中的传播速度是影响埋深计算精度的关键参数之一.本文通过吸取几种波速求取方法的优点,给出一种精度高、操作性强的波速求取法—刚性界面反射系数法;并利用此法,由LTD探地雷达实测数据求得整条测线的速度曲线.经检验,借助于少量钻芯数据,利用此法可使公路面层厚度检测的相对误差小于5%.

In detection of underground target by Ground Penetrating Radar(GPR), the estimation of EM wave velocity is very important for buried depth. In this paper, a accurate and operable method to estimate EM wave velocity, called the reflectance method opposite rigid interface, was proposed. Then a velocity curve of EM wave is given along profile from LTDGPR data by this method. With the help of a few of core samples, detecting error of GPR for the thickness of asphaltum layer on highway is less than 5% via this method.