Advance Geological Prediction Of Yaoshan Tunnel Of Zheng-Xi Expressway

In recent years,with the rapid development of China's national economy,the number of mountain tunnel construction is increasing,as well as the large-scale construction of high-speed railway,expressway,urban rail transit,the cost,environmental impact,and other projects.Tunnel engineering is a kind of concealed engineering,which is often affected by lots of bad geological bodies.If the bad area that cannot be accurately predicted before or during the tunnel,it may affect the construction progress,even cause catastrophic accidents,and bring invisible dangerous and economic losses.Therefore,it is very important for tunnel construction to master the geological conditions before excavation.Geological prediction of tunnel is an effective method to solve this problem.Based on Yaoshan tunnel of Zhengxi high speed,this paper introduces the common geological prediction methods such as seismic wave reflection method,transient electromagnetic method and geological radar method,and discusses the applicability of various geological prediction methods in this project.This paper puts forward a method to determine the grade of surrounding rock for the comprehensive geological prediction of Yaoshan tunnel,that is,to use GPR to make advance geological prediction,to determine the grade of surrounding rock within the detection range,to obtain the actual accumulated value of surrounding rock deformation within the prediction section through the deformation monitoring and measurement of surrounding rock,to generate the surrounding rock deformation curve,and to analyze the deformation of surrounding rock according to the existing model of surrounding rock clearance convergence deformation According to the data correlation and fitting degree,the grade of surrounding rock is analyzed and verified.On this basis,the quality of the tunnel lining in the study section is detected by GPR,and the results show that the convergence data of the clearance truly reflects the deformation of the surrounding rock.The main results of this paper are as follows:(1)In other geological areas of Yaoshan tunnel,TGP is used to make advance geological prediction,and inversion regression analysis is carried out on the measured data,and good results are obtained.(2)In this paper,the advanced geological prediction and field monitoring of Yaoshan tunnel by GPR are carried out,and the inversion regression analysis of the measured data is carried out,and the quantitative analysis of its correlation and fitting degree is carried out to simulate the tunnel model in the observation section.NDT for lining of Yaoshan tunnel observation section,and the surrounding rock grade is determined by combining with the model analysis of observation section.(3)Good results have been achieved in the detection of the other three application sections of Yaoshan tunnel,which proves that this method can be a basis for the determination of surrounding rock grade.