隧道掌子面前方空洞的正演模拟与模型试验研究

Forward simulation and model test of cavity in front of the tunnel

隧道开挖过程中经常会遇到空洞等不良地质,严重影响了隧道施工安全与顺利完成。为了准确掌握隧道掌子面前方空洞的地质雷达图像反射信号特征,本文采用时域有限差分软件对隧道掌子面前方不同大小空洞进行正演模拟,并与室内模型试验采集的地质雷达时间剖面进行对比分析。结果表明:地质雷达可以探测到空洞的埋深与深度尺寸,矩形空洞地质雷达反射波呈现前部扁平的双曲线特征,并有多次波反射。该研究成果对于提高隧道超前地质预报现场解释提供了一定参考。

Cavities and other adverse geological conditions are often encountered in the process of tunnel excavation,which seriously affect the safety and successful completion of tunnel construction.To accurately grasp the characteristics of ground penetrating radar reflection signal for cavities in front of the tunnel,forward simulation of different cavities in front of the tunnel was carried out by time-domain finite difference software.The time profile of GPR collected by model test was compared and analyzed.The results show that the GPR can detect the buried depth and depth dimension of cavities in front of the tunnel,and the GPR reflected waves of rectangular-like cavities have the characteristic of near-flat hyperbola at the front and multiple reflections.The results of this study provide some reference for improving the interpretation of tunnel geological prediction.