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针对探地雷达信号在富水裂隙岩体中的图像与频谱特征,开展了非频散介质与频散介质条件下时域有限差分正演模拟,模拟结果体现了频散介质条件下电磁波在岩体与裂隙水之间的高衰减率、相位差、震荡反射、有限的探测深度以及频散等特性。利用基于连续小波变换的小波尺度谱,把模拟信号同时在时域和频域内分解,显示了频散介质中低频信号产生过程。信号中低频成分逐渐增多,并且表现为从稳定到不稳定状态。与实测富水裂隙砂岩区的探地雷达信号分析对比,解释了探地雷达在富水裂隙岩体中信号特性。
Aiming at the image and frequency spectrum characteristics of GPR signal in water-rich fractured rock mass, a finite-difference time-domain finite-difference forward modeling is carried out under non-dispersive and dispersive media conditions. The simulation results show that the electromagnetic wave in rock High attenuation rate between body and fissure water, phase difference, shock reflection, limited detection depth and dispersion. Using wavelet scale spectrum based on continuous wavelet transform, the analog signal is decomposed in the time domain and the frequency domain at the same time, which shows the process of low frequency signal generation in the dispersion media. Signal in the low-frequency components gradually increased, and the performance from stable to unstable state. Compared with the ground penetrating radar signal analysis of the actually measured water-rich fractured sandstone area, the signal characteristics of the GPR in the water-rich fractured rock mass are explained.