隧道衬砌空洞探地雷达图谱正演模拟研究

Research on forward simulation of tunnel lining cavity GPR images

探地雷达作为一种高效、先进的无损检测设备,能够对隧道衬砌实施连续扫描,实时获得雷达图谱。然而,由于探地雷达在我国的应用时间还非常短暂以及雷达图谱的复杂性,隧道衬砌空洞探地雷达图谱的辨识还存在一定的问题。据此,通过不同环境的试验得到空洞雷达图谱特征,并利用二维时域有限差分法对衬砌空洞雷达图谱进行正演模拟。采用VC++语言编写探地雷达正演模拟程序,对隧道衬砌检测中常见的几种空洞模型进行正演模拟,得出模拟波形和图谱,并与实测隧道衬砌空洞的探地雷达波形和图谱进行对比。结果表明,模拟图谱与实测结果相似,具有较明显的空洞特征。良好的结果也验证了二维时域有限差分法(2D-FDTD)正演模拟的可行性。

With the advantages of efficiency, advancement and non-destruction, ground penetrating radar （GPR） can scan the lining of tunnels successively and obtain objective and accurate images. Because of the transitory application of GPR in China and the complexity of radar images, there are still some problems in the identification of cavity radar images. Accordingly, through various tests the cavity feature is obtained; and GPR waves and images of tunnel lining cavity are simulated using 2D-FDTD. Finally, a forward numerical simulation program is developed with VC＋＋, which simulates a few familiar cavity models in detection of tunnel lining. Comparing the simulated waves and images with the measured, and it is shown that the simulated, which has the cavity feature, is similar to the measured. The good results verify the feasibility of 2D-FDTD.