Applied Research Of Ground Penetrating Radar In Tunnel Geological Prediction

In the process of modern tunnel construction, we conduct advanced geological prediction in the way of geophysical prospecting, which has the very vital significance to grasping the geological condition accurately, reducing construction accidents, ensuring the safety of personnel life in the construction and construction schedule. Among many geophysical prospecting methods, ground penetrating radar, owing to its simple operation, high resolution, fine frequency cap, intuitive image, high accuracy, has a promising future.At present, there remain many problems in the GPR's application of tunnel geological prediction, such as the normalization of site operation, the rationality of parameter setting, processing method of data and the uniqueness of interpretation about the detecting results, those have to be perfected and improved, therefore this paper bases on the results of the application and data interpret of geological radar at home and abroad, combined with the practical application of GPR in four tunnels, that does the following works:(1) Based on introducing the basic principle of the GPR, with the software module in the environment of MATLAB, the GPR modeling simulation analysis software is developed, with which realizes the function of showing image of a new domestic GPR results, data analysis and processing.(2) The numerical modeling simulation about the process of electromagnetic wave propagation in the tunnel advance geological forecast is applied in this paper, the analysis model of typical geological structures (such as the unbroken surrounding rock, the shattered fault zone, water zone ,the cave and the water-bearing cave) is built, then, the corresponding radar reflection are gained, according to the modeling results, the general rule of interpretation about GPR's images is got.(3) In the base of above results, combined with the application of GPR in tunnel advance geological forecast, Summarized a set of standardized work methods, including the layout method of measuring line in detection, detection parameter setting and the matters which should be noted in the detection process; by referring and correcting the characteristics of the radar detection images which get in the specific geological condition, the detection images which get in practical engineering by GPR are interpreted, hence, the accuracy and rationality of the forecast results are improved, the related actual excavation of tunnel proves the validity of this method.