基于时域有限差分法的探地雷达数值模拟及在隧道超前地质预报中的应用

Numerical simulation of GPR based on finite-differencetime-domain method and its application in tunnel geological forecasting

为准确识别探地雷达反射波形特征,笔者采用有限差分方法分别建立岩溶、岩性接触带以及断层破碎带模型,模拟隧道超前地质预报中遇到的典型不良地质体。通过分析其反射波波形特征,对比了西康高铁以及新西成铁路工程实例中岩溶和断层破碎带预报结果,结果表明模拟的雷达波形特征可以作为探地雷达预报典型不良地质构造时参考的波性特征,可以提高预报结果的准确性。

To accurately identify the reflection waveform characteristics of ground penetrating radar(GPR),the authors employed the finite-difference method to establish models for karst model,lithologic contact zone model,and fault fracture zone model.These models simulate typical unfavorable geological bodies encountered in tunnel geological forecasting.By analyzing the waveform characteristics of reflected waves,the study compares forecast results of karst structures and fault fracture zones in the engineering cases of the Xi an-Kunming High-Speed Railway and the New Xi an-Chengdu High-Speed Railway.Results indicate that the simulated radar waveform characteristics can serve as reference wave features for forecasting typical unfavorable geological bodies using GPR,thereby enhancing the accuracy of forecast results.