论文部分内容阅读
衬砌空洞是运营隧道中的常见病害,由于其内部介质复杂,尤其当积水存在时,探地雷达(GPR)识别存在较大难度和误差。针对空洞积水的情况,利用MATLAB编程,建立空洞和不同电导率的空洞积水数值模型,用时域有限差分法(FDTD)进行探地雷达二维正演模拟,通过分析正演图谱和单道波形,得出空洞及积水的响应规律。制作隧道衬砌混凝土模型,应用探地雷达扫描测试,并与正演模拟结果进行对比分析。结果表明,雷达正演与模型试验结果相似;未积水的空洞反射波相位与入射波相反;空洞积水的雷达信号反射更明显,其反射波相位与入射波相同;电磁波在水介质中迅速衰减,空洞积水时,其大小难以定量识别。
Lining hollow tunnel is a common disease in tunnels. Due to its complicated internal media, GPR recognition is difficult and error-prone, especially when water is in existence. Aiming at the problem of empty ponding, a numerical model of cavitation and hollow cavitation with different electric conductivity is established by using MATLAB programming. Two-dimensional forward modeling of GPR is carried out by FDTD method. Waveform, draw the cavity and water response law. The tunnel lining concrete model was made. The ground penetrating radar scanning test was applied and the results were compared with the forward simulation results. The results show that the radar forward modeling is similar to the model test results. The phase of the hollow reflection wave without water is opposite to that of the incident wave. The reflection signal of the hollow water water reflection is more obvious and the phase of the reflection wave is the same as that of the incident wave. Attenuation, empty water, its size is difficult to quantitative identification.