Study On Construction Control Technology Of Huangtuling Ultra Shallow Buried Bias Pressure Tunnel Crossing The Ancient Great Wall

With the rapid development of China’s economy,the application of highway tunnel is more and more extensive.China has a long history,many areas still retain these ancient buildings,the ancient Great Wall and so on,so we must pay attention to the protection of these ancient buildings when building tunnels.Based on the background of Huangtuling tunnel passing through the ancient Great Wall,this paper studies the settlement control standard of the tunnel passing through the ancient Great Wall,as well as the influence of advance support scheme and different construction schemes on the foundation of the ancient Great Wall,and then selects the optimal construction scheme to ensure the minimum impact on cultural relics during the tunnel construction.This paper mainly studies the following aspects.1.According to the existing literature and research results,and using FLAC3 D numerical calculation software to simulate the section of Huangtuling tunnel under the ancient Great Wall.Taking the local inclination value of the ancient Great Wall as the standard to judge whether it is safe or not,the vertical displacement of the foundation of the ancient Great Wall is studied,and the settlement control within 20 mm is the best when the tunnel passes under the ancient Great Wall.According to the regression analysis of the vibration velocity and stress of the ancient Great Wall,the calculation model of the safety threshold of the vibration velocity is obtained,and the blasting vibration velocity of the ancient Great Wall is determined to be controlled at 2cm/s.2.Establish three-dimensional calculation models under three working conditions: no advance support measures,small conduit grouting for left and right tunnels,and small conduit grouting for left and right tunnels,and large pipe shed and middle tunnel.According to the calculation results,the displacement around the tunnel and the surface settlement data are analyzed.Finally,it is determined that the advance support measures of large pipe shed + small pipe are the most favorable for the project.3.The fast Lagrangian difference analysis program FLAC3 D software is used to simulate the construction process of the ultra shallow buried partial pressure section of Huangtuling tunnel,including the side wall heading method,the CRD method and the CRD + CD method.Through the comparative analysis of the surface settlement,the displacement in the tunnel and the rock stress around the tunnel,the best construction method for the section of Huangtuling tunnel passing through the ancient Great Wall under the actual engineering conditions is obtained Side wall heading method.4.On the basis of the selected construction method,first simulate the three working conditions after the excavation of the middle guide tunnel,namely,the first construction of the deep side guide tunnel,the first construction of the shallow side guide tunnel,and the simultaneous construction of the two side guide tunnels,then simulate the two working conditions: the first construction of the deep side main tunnel and the first construction of the shallow side main tunnel,then compare and analyze the surface settlement,the displacement and stress of the middle wall,and finally get the results of the simultaneous construction of the two sides The scheme of constructing the shallow side main tunnel after the pilot tunnel.5.Finally,the correctness of numerical simulation and the feasibility of technical measures are verified by comparing the monitoring data of construction site with the results of numerical simulation.