Layer recognition and thickness evaluation of tunnel lining based on ground penetrating radar measurements

摘要: Abstract Ground penetrating radar (GPR) is a time-dependent geophysical technique for measuring the thickness of second lining, which one most important tunnel quality targets. As wave transmits from air (or lining) to lining first lining), Fresnel reflective coefficient negative, i.e., phase reverse incident. In dimension time-waveform diagram (A-Scan) GPR, layers are located on inflexions decided by reflection coefficients and attenuation electromagnetic in transmission medium. By towing antenna over surface, two scanning data (B-Scan) constituted multiple A-Scan channels, where grey scale applied amplitude values. process exploration, interfaces separately plotted connecting each maximum peak point or A-Scan. Long Hai Tunnel, artificial recognition provides 15 sampling values exploration line D9 + 015.195 D9 + 065.195. However, automatic can provide more information, such as average thicknesses, standard errors qualification rates thickness, etc.