Tunnel lining cavity is one of the diseases that threaten the safe operation of tunnel, so it has been the attention of test personnel. As a nondestructive testing method, Ground Penetrating Radar (GPR) has been widely used in tunnel lining disease inspection. In order to improve the detection accuracy and success rate of tunnel lining cavities, this paper applies the reverse-time migration (RTM) algorithm to image tunnel lining cavities with high accuracy. Firstly, the principle of GPR pre-stack RTM is described in detail, in which the finite difference time domain (FDTD) method is used to calculate the forward and backward electromagnetic fields, and the normalized cross-correlation imaging condition is used to obtain the RTM results. On this basis, the GPR RTM program is compiled and applied to the simulated dataset of a typical lining cavity GPR model. The comparison of RTM and Kirchhoff migration result showed that the diffracted wave in the steel bar and cavities has good convergence, and the profile’s resolution is improved effectively; In contrast to the Kirchhoff migration result, the RTM result can better focus the radar diffraction wave energy of the steel bars and cavities on the real space location generated by them, weaken the shielding effect of the steel mesh, and suppress multiple interference and clutter scattering waves. Finally, a physical model of lining cavities was detected by GPR, and the RTM algorithm was applied to data processing and interpretation. The RTM delimits the positions of steel mesh and cavities effectively, and the interpretation accuracy of GPR profile has been improved, which provide a scientific and effective way for accurately delimit the scope of tunnel lining cavities.

隧道衬砌腔是威胁隧道安全运行的疾病之一，因此一直受到测试人员的关注。作为一种无损检测方法，探地雷达（GPR）已广泛用于隧道衬砌病害检查。为了提高隧道衬砌空腔的检测精度和成功率，本文将逆时偏移（RTM）算法应用于隧道衬砌空腔的高精度成像。首先，详细介绍了GPR叠前RTM的原理，其中使用时域有限差分（FDTD）方法计算正向和反向电磁场，并使用归一化互相关成像条件来获得GPR叠前RTM的原理。 RTM结果。在此基础上，GPR RTM程序被编译并应用于典型衬砌腔GPR模型的模拟数据集。RTM和基尔霍夫迁移结果的比较表明，在钢筋和型腔中的衍射波具有良好的收敛性，有效地提高了剖面分辨率。与基尔霍夫迁移结果相反，RTM结果可以更好地将钢筋和型腔的雷达衍射波能量聚焦在它们产生的实际空间位置上，削弱钢筋网的屏蔽效果，并抑制多重干扰和杂波散射波浪。最后，通过GPR检测了衬砌腔体的物理模型，并将RTM算法应用于数据处理和解释。RTM有效地划定了钢网和型腔的位置，