Comprehensive Technology Study On Soil Two-Lane Highway Tunnel Of Ultra-Shallow Undercrossing Multi-Line Railwawy And Expressway

This paper studies comprehensive techniques of ultra-shallow railway tunnel and highway tunnel by the background of Gaoqi Tunnel and has a strong practical value. This paper has done following work:(1) The paper has collected a large number of engineering examples by the use of advanced support technology of pipe roof and selected 10 case similar tunnel project in Xiamen. Design parameters of pipe-roof, construction techniques and the effect of ground settlement controling are focused on. The scope of support parameters and settlement control standards are obtained in this project.(2) Support parameters suitble for this project are gotten by numerical calculating and analyzing field data on different parameters of the pipe-roof.(3) Due to compare and analyze prediction methods of ground settlement caused by a variety of shallow tunnel excavation it ultimately determines that by the settlement formula induced by the unit excavation and any arcs, integral formula has being derived and improving, and the surface settlement formula with loads ultimately comes out on the basis of the random theory.(4) Home and abroad advanced support methods and their characteristics are analysed and ultimately the pipe roof advanced grouting method is applied in this project.(5) Mumerical calculating method is used for comparing and analyzing the construction safety of composite repair and separate repair tunnels. It is founded that the programme of separate repair is better than that of composite repair by comparing the mechanical behavior after excavation and the displacement caused by two programs.(6) The optimal tunnel construction process is obtained and the temporary support are needed in construction by the use of numerical methods for the construction process of underpassing railway and highway tunnel and for whether adding temporary bracing in different conditions.(7) Ground settlement law is obtained and the request on top speed of the train is proposed by analyzing ground center subsidence in considering the case of dynamic loads.