Improvement Of Ground Penetrating Radar And Its Application Into The Predication Of Geological Conditions In Tunnel Engineering

Prediction of geological conditions is a highly concerned but hard to deal with problem before excavation of tunnel in engineering geology and tunnel engineering both at China and aboard. Ground penetrating radar is a newly developed nondestructive detection technique. Compared with routine detections, it is effective, fast, continuous, non-destructive, and easy for operation with good anti-interference, low cost and high resolution imaging. Ground penetrating radar has become one of the most important fields for study in engineering.Based on the radar detection theory, from its detection capability, parameters setting, and profile explanation, this paper studied the feasibility for application of ground penetrating radar into the prediction of unfavorable geological conditions in highway tunnel construction. The theoretical principle of ground penetrating radar is the propagation of electromagnetic wave through media. According to this theory, electromagnetic wave equation, electromagnetic field of dipole antenna and time field and space field of electromagnetic wave were all established. This paper also studied the reflector, refraction, transmission, scattering and diffraction of radar wave propagation through inhomogeneous media. It summarized the electromagnetic properties of electromagnetic field of high frequency through the medium of ground, and the propagation and weakening of radar wave through different terranes. For the special detection circumstance of tunnel construction, analyses at the data and display mode were performed. Date reading interface of SIR-20 ground penetrating radar was developed. As to the interference to the radar signals by surrounding of tunnel, wavelet resolution for noise suppression and K-L transforming were successfully applied in post treatment of ground penetrating radar signals. Based on electromagnetic wave properties of ground penetrating radar through media, analysis was performed on the imaging theory and arithmetic to establish kirchnoff integral method, finite-difference method and frequency-wave-number domain method. Its real time application also came true.Based on the detection with ground penetrating radar for whole Lingshi tunnel construction, which is a section of highway reconstruction from Jiexiu to Huozhou. The results show that ground penetrating radar can be used in various geological conditions. It is reliable for the unfavorable geological disaster prediction in front of tunnel face.