堤防工程是我国防洪体系中的重要环节。针对堤防中潜在隐患缺陷体,根据不同缺陷体介质的电性特征,建立了相应的堤防隐患模型。依据时域有限差分(FDTD)算法和完全匹配层(PML)的吸收边界条件,构建相应的堤防隐患缺陷体地球物理模型,使用GprMax 2D软件结合自行开发的MatLab程序,获得探地雷达正演波形图。通过波场特征分析,可知不同形态、构造位置和电性参数的隐患缺陷体的探地雷达反射波幅值和形态是不同的。正演结果能准确反映隐患缺陷体的深度、水平位置等空间特征。结合长江四邑公堤堤防隐患探测项目的2个工程实例分析可知,雷达正演模拟与探测剖面结果和工程验证基本一致,表明探地雷达能够有效地探测堤防隐患,该正演方法切实可行。分析典型隐患模型的波场特征有助于指导后期解译工作,从而对缺陷体从定性到定量进行更精确的解译,确保堤防工程的安全运行,保障汛期人民的生命财产安全。
Abstract
In view of the electrical characteristics of the media of different potential geological defects in embankment, corresponding geophysical models are built using the finite difference time domain (FDTD) algorithm with the perfectly matched layer absorbing boundary conditions (PML). GprMax software together with MatLab self-programming is employed for the GPR forward simulation. Result reveals that the amplitude and form of GPR reflected wave of hidden defects vary with shape, location, and electrical parameters. Forward simulation result accurately reflects the depth and horizontal position of hidden defects. Two engineering examples demonstrate that the results of GPR forward simulation are basically consistent with engineering verification, which proves that GPR can effectively detect the hidden dangers of embankment. The GPR forward simulation method is feasible, and is helpful to guide the further interpretation work more precisely.
关键词
堤防隐患探测 /
探地雷达 /
隐患缺陷体 /
时域有限差分算法 /
地球物理模型 /
波场特征 /
正演模拟
Key words
detection of hidden dangers in embankments /
ground penetrating radar (GPR) /
hidden defective body /
finite difference time domain(FDTD) algorithm /
geophysical model /
wave field characteristics /
forward modeling
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参考文献
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基金
国家重点研发计划项目(2017YFC1502605);国家自然科学基金项目(41702321)
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