| Ground Penetrating Radar is one of the geophysical exploration methods which used ultra-high frequency pulse electromagnetic wave detecting the distribution of media in shallow and super-shallow underground, it is more widely used on inspection of tunnel lining, because of its non-destructive, efficient, anti-interference ability, easy operation, low cost, subject to conditions detected a small, high precision, continuous scanning for tunnel. at the current, tunnel testing techniques are basically two-dimensional, which is more difficult to provide accurate information for disease of bad shape, size, spatial form, and the image interpretation has been more great subjectivity and empirical. Therefore, it is important to carry out the inversion theory research on the two and three-dimensional probe, determine the size of tunnel lining and shape inside the cavity quantitatively; provide the basis for testing by explaining the maps. This paper study on the inversion of ground penetrating radar theory in the cavity of tunnel lining systematically, by the physical model test, numerical simulation, digital signal filtering and data retrieval, and apply the second, three-dimensional joint detection method to engineering practice, the main contents and results are as follows:①This paper demonstrated the impact on the model-border when collected the data by the use of ground penetrating radar, and as a basis for the design of the tunnel lining within the empty physical model, two, three-dimensional radar detection as used to detect empty physical model ,and the software of reflex and easy-3D was used to deal with the data, promote the three-dimensional quality inspection tunnel reasonable line spacing, and using MATLAB programming visualization the three-dimensional image of lining detection and by radar profile, the radar section of the different display forms, summed up the square empty two, three-dimensional map features.②Aimed at the features of non-stability and nonlinear pulse signal attenuation belong to penetrating radar signals. The multi-wavelet theory is introduced in the radar noise reduction, CL4 balance multi-wavelet in ground penetrating radar signal processing filtering algorithm is detailed derived, and lab test data and field test data of the signal filtering used programming of MATLAB and achieved good results.③Take the Maxwell equations of ground penetrating radar transmission mechanism for example, the conductive medium of two-dimensional TM wave and three dimensional forward modeling and without considering the medium in the magnetic loss of UPML absorbing boundary conditions are derived in detail which was used the matching condition of no reflection matrix, the model area and absorbing boundary zone of discrete FDTD forward difference formula was derived. and a variety of two-dimensional models and three-dimensional rectangular cavity empty was put into the forward simulation model using MATLAB programming, while the RAMAC with MATLAB programming GPR system data conversion, that is, the radar data files stored in various information and data files to read into *.rd3 format.④The general mathematical and physical model form of the three-dimensional and two-dimensional inversion of ground penetrating radar was derived; the Tikhonov regularization method was introduced in dielectric constant inversion of ground penetrating radar, and configuration of ground-penetrating radar system inverse dielectric constant objective function. Prepared using MATLAB based on real-coded genetic algorithm process Tikhonov regularization method, the use of inversion programs to inversion the dielectric constant of the two-dimensional on cavity model and the trapezoidal model.⑤Proposed the joint detection method of tunnel testing on the two and three-dimensional and applied to Danan Mo and XInan Gou 1 # Tunnel of the first contract in Xin Bao Expressway, for the realization of radar detection of tunnel lining in this paper builds a new road by using the qualitative description to the quantitative application.
|
PDF Full Text Request