Research Of Tunnel Face Geological Conditions Detection Method

It is very important to discover the geology in front of the tunnel in advance in the process of the tunnel excavation because it can provide quite accurate geology data for the construction, adjust the construction craft in time, reduce and prevent the occurrence of the engineering accidents. This text mainly introduced two probing methods in the geology conditions, geological radar and induced polarization method of electrical prospecting method. Geological radar is a non-destructive test instrument that detect the underground objects by the quality of discontinuousness of the underground medium. The theory of induced polarization method is based on the difference of resistivity of rocks, ores in the various underground of three-dimensional space, through the observation of the current market distribution point on the ground, underground geological conditions can be speculated.The basic theories about the geological radar probing and experimental data analysis are described. Commencing from the basic theories of the electromagnetic wave, the wave equation of the electromagnetic wave is introduced, the rules such as the transmission, the wave speed, the reflection of the radar wave are expatiated. Analysis of geological radar detection performance, including geological radar resolution and detection of depth. Choose the appropriate parameters for profile scanning measurement. Using digital signal processing technique with the data collected, including data editing, format conversion, read head files and data files, power spectrum analysis. Experimental analysis of geological radar signal noise sources, using three method for experimental data processing. In contrast of geological radar images before and after processing, analysis of the pros and cons of process, give interpretation to the processed image, through analysis, the detecting region's geological conditions is obtained. Then, measuring principle of induced polarization method and experimental data analysis are described. Analysis induced polarization effect of the parameters. Symmetric four electrode device is used, dispersion rate with the depth of change is concluded. The article carries on the summary to the work in the end, and puts forward the suggestion to the work of further demand with Signal Source, electrode and digital oscilloscope.