中文摘要：

公路隧道衬砌的缺陷直接关系到衬砌运营寿命。以公路隧道衬砌检测为研究背景,建立隧道工程中常见的衬砌结构缺陷的几何形态模型。首先,研究电磁波的不同子波主频的探测性能以及分辨率;其次,根据缺陷的几何形态建立其地电模型,以脱空厚度、圆形缺陷、矩形缺陷以及不同填充物如砂土、水、空气为主要研究内容,通过时域有限差分（FDTD）法模拟分析其成像特征及差异。研究结果表明：衬砌脱空厚度的增加引起深部目标体成像位置更接近扫描面;缺陷的几何形态对成像特征影响小于填充体的影响;含水填充体的电磁波成像特征比气体及砂土填充体更加明显,且对电磁波的吸收作用导致对深部目标体的产生多次波等干扰因素。

英文摘要：

The lining defects of highway tunnels affect directly the life span of the lining. A geometric model of the defects of lining ~tructures in highway tunnels was established. The detection performance and the resolution in different wavelet frequency were studied. A geoelectric model of lining on the basis of common defects was presented considering the shape and the thickness of voids, the circular and rectangular defects and the different fillings such as sand, water and air. The imaging characteristics and differences were simulated using finite difference-time domain（FDTD） method. It is found that the increase of the thickness of voids leads the imaging position of deep target to get closer to the scanning surface. The effect of the geometry of defects on the imaging features is smaller than that of fillings. The characteristics of electromagnetic wave imaging of water contained fillings are found to be more noticeable than those of air fillings and sand fillings. Water fillings absorbs the electromagnetic waves and bring about interference factors such as multiple waves from deeper targets.