Study On Comprehensive Geological Forecast On Long And Large Tunnel Under Complicated Geological Conditions

The long and huge tunnels are often buried deeply and have complex geological ploblems, in the initial survey, it's difficult to accurately identify the hydrologic and geological conditions. Advanced geological forecast can be used to find geological conditions changes, and achieve the purpose of taking measures in advance and controlling risks.Through the way of geology investigating, theory analysis, numerical modeling and field testing, this paper did some researches on the comprehensive geological forecast on long and large tunnels under complicated geological conditions. The main research contents and results are as follows:â‘ This paper introduced and compared some common methods of geological advanced forecast, and expounded emphatically the detection method, detection apparatus, data acquisition and data processing of Ground penetrating radar(GPR), also the principle and method of Tunnel geology prediction(TGP). Considering the advantages and disadvantages of various forecasting methods, this paper put forward the operating processes of the comprehensive geological forecast method, which is based on the geological analysis, with GPR as the core and seismic reflection method for assistance.â‘¡Due to the geological analysis is the basis of geological advanced forecast, some detailed geological surveys in Yunzhong montain tunnel were down. The geological and hydrogeological characteristics in tunnel site was mastered, the type of geological disasters that may occur in Yunzhong Montain tunnel were analysised.â‘¢This paper wrote a Mtalab program with FDTD method to simulate the intact rock, fault fracture zone, water enriched zone and cave, 11 common GPR images at different scale, angles, size and filler were finally obtained.â‘£The comprehensive geological forecast method was put in application in Yunzhong Montain tunnel. Through the engineering verification, after the analysis of accuracy, continuity, betimes, degree for construction influence, etc., what the conclusion drawn is that the comprehensive geological forecast method can meet the demand of long and huge tunnel construction under complicated geological conditions .