关键词: 隧道超前预报, 探地雷达, 干扰因素, 典型不良地质体, 雷达干扰图像特征

Abstract: In order to apply ground penetrating radar(GPR) to accurate advanced geological prediction in tunnel engineering, we discussed the causes of common interferences and their influences on data interpretation, and determined the reflected interference information in profile of GPR image. Then, we gave examples of the antenna coupling and metal interferences and put forward precautions to avoid interference in the process of collecting GPR data. On the basis of three examples, we introduced the prediction of bad geological bodies such as karst cave, fault fissure water, and weak interlayer. Through analyzing typical characteristics of waveform, frequency and amplitude of the profile, we predicted the type of bad geological body as well as the spatial distribution characteristics like location and structure strike ahead of the working face of the tunnel. The prediction results are basically consistent with the distribution of bad geological bodies revealed by excavation, which proves that GPR is feasible and effective in the prediction of common bad geological bodies. By summarizing and analyzing the common radar interference images and the profiles of GPR images of typical geological bodies, we can provide references of interpreting complex geological bodies more precisely for geophysical workers and ensure the safety of tunnel construction.

Key words: advanced tunnel geological prediction, ground penetrating radar (GPR), interference factor, typical bad geological body, interfered radar image features