基于GprMax的隧道超前预报雷达正演模拟及应用

发布时间：2018-04-01 01:01

本文选题：探地雷达　切入点：复杂不良地质体　出处：《人民长江》2017年07期

【摘要】：针对隧道超前预报可能遇到的不同不良地质体,根据其介质电性特征,构建相应的地球物理模型,基于时域有限差分算法(FDTD)和完全匹配层(PML)的吸收边界条件,利用GprMax软件,结合matlab编程开展地质雷达正演模拟。研究结果表明,对于充填不同物质的溶腔模型,由于反射系数大小的差异,反射信号同相轴的强弱和形态有所不同,不同的地电模型其相位、振幅、波形特征都各不相同。结合2个工程实例,雷达正演模拟和实测剖面结果与实际开挖情况基本相符,验证了该正演方法的可行性,说明探地雷达能有效地勘察不良地质体的类型、位置、构造走向等空间分布特征,有助于更好地指导物探工作者对复杂地质体进行更精确的解释,确保隧道施工安全。
[Abstract]:In view of the different bad geological bodies which may be encountered in the tunnel advanced prediction, according to its dielectric electrical characteristics, the corresponding geophysical model is constructed. Based on the absorbing boundary conditions of the finite-difference time-domain (FDTD) algorithm and the perfectly matched layer (GprMax), the GprMax software is used. Combined with matlab programming, the forward modeling of GPR is carried out. The results show that the intensity and shape of the phase axis of the reflected signal are different due to the difference of reflection coefficient for the cavity model filled with different substances. The phase, amplitude and waveform characteristics of different geoelectric models are different. Combined with two engineering examples, the results of radar forward modeling and measured profiles are basically consistent with the actual excavation situation, which verifies the feasibility of the forward modeling method. It is shown that GPR can effectively investigate the spatial distribution characteristics of bad geological bodies, such as type, location, structural strike, etc., which is helpful to guide geophysical prospectors to interpret the complex geological bodies more accurately and to ensure the safety of tunnel construction.
【作者单位】：长江科学院水利部岩土力学与工程重点实验室;
【基金】：长江科学院院所基金(CKSF2016045/YT)
【分类号】：U452.11

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