Study Of The Application Of Ground Penetrating Radar To Advanced Geology Forecast For Youzhushan Tunnel

In this paper, the basic theories for geological radar are summarized, such as the transmission theory, refraction theory and reflection theory, of electromagnetic wave in the stratum, among which detection principles, detection distance, resolution for geological radar are stated in detail.Through the analysis for the tunnel in karst area, the regularity of development of disasters in such areas were explored and stated under different circumstances:horizontal stratum, titled stratum and syncline. This regularity mentioned above includes the type of disasters in karst area, the scope of the influence and the direction of these disasters. Based on such exploration for the regularity, the graph of geological model for karst development was plotted.This geological model for karst development, together with the investigation report and the geological condition of tunnel face, was then employed to analyze the state of karst disasters development. By virtue of the analysis, the operation for Ground Penetrating Radar (GPR) can be continuously adjusted accordingly, and then more accurate results were obtained. The procedures of using GPR are as follows:(1) according to the roughly location, radar lines for detection are arranged (2) based on relevant information, adjust the approach to collect and process data; by virtue of the geological information, eliminate the disturbance signal and then enhance the signal of interest;(3) together with the geological information and geological model for karst development, data are presented and explained growingly. It is found that this set of proposed approach to forecast the karst disasters in tunnel is more efficient, more accurate.Youzhushan tunnel belongs to the engineering project of railway from Guizhou to Guangzhou. The proposed approach is utilized to forecast the karst disasters behind the tunnel face in the construction for Youzhushan tunnel, such as the karst cave, water-eroded groove etc. Among the construction, the results obtained from the proposed approach were checked, and these results were roughly consistent with the real-life condition behind the tunnel face. Therefore, the proposed approach has provided accurate geological information during the construction, offering the safeguard for the safety in construction, construction quality and construction duration.