Study On Cross-hole Resistivity Computed Tomography Method In Subway Of Karst Area

With the acceleration of urbanization, in order to meet the needs of transport, many cities are being or planning on building underway. However, in the karst areas, there exist some unfavorable geological body may cause serious harm to construction work of subway, such as karst caves, water, faults and weak fracture zones. Successful prediction of these unfavorable geological body can help constructer to take timely measures and reduce losses.Cross-hole resistivity computed tomography(CT) is an geological forecast method using resistivity characteristics of rock and soil. At present, research of cross-hole resistivity method in urban subway is less, in order to improve the level of practical application of this method, the work of this paper Include the following aspects:(1)Typical geological body’s occurrence form and characteristics were Analyzed and concluded, several models apply to city subways were established, laid the foundation for the numerical simulation.(2)For several typical geological hazard body in urban subway, simulation work were carried out and response characteristics were obtained. Simulation results of different operating parameters were compared, the effects of different operating parameters on the detection results were analyzed, the data observation method was optimized.(3)By data normalization, differential and other mathematical methods, combined resistivity contour imagery, presents high resolution interpretation methods for cross-hole resistivity work, helpful in improving accuracy of data interpretation.(4) Based on the working conditions in city subway, proposed several data collection methods, application engineering in Dalian metro verified the appropriate results of this study, summed up several useful methods in cross-hole resistivity techniques. Theoretical research and practical results show that the cross-hole resistivity CT methods has several advantages:higher accuracy, greater flexibility, more time saving and better detection effect to geological body. Research work shows that the cross-hole resistivity CT methods is an effective supplement to geological prediction methods in city, which there is a good theoretical significance and engineering application value.