Study On Construction Technology Of Shield Tunnel Pushed Through Existing Mine Tunnel

With the rapid progress of urban development in our country,a large number of people have poured into the city,and traffic problems have gradually become an important factor hindering urban development.Metro rail transportation has the characteristics of "large transportation volume,fast speed,and not occupying ground space".It has become the first choice to solve the problem of urban traffic congestion.Metro rail construction is the most widely used shield method,and in some complex conditions The medium shield method cannot independently complete the subway trac K construction.Therefore,we use the shield to push and assemble the segments in the hollow of the primary tunnel of the mine method and grouting to form the secondary lining tunnel.TaKing Hefei Metro Line 3 Qianshan Road to Shihe Road Section Subway Air Push-through Mining Tunnel Construction as the engineering bac Kground,the finite element software Midas/GTSNX was used to establish a three-dimensional analysis model,and the shield machine air-lifting construction technology was studied,and the following conclusions were obtained.（1）When the height of the piled gravel in front of the cutter head is D/3（D is the diameter of the cutter head）,the pile length L=KD,when the coefficient0.51.5,and increasing the value of K has little effect on the surface settlement.（2）When the height of the piled gravel in front of the cutter head is D/2（D is the diameter of the cutter head）,the pile length L=KD,when the coefficient0.51.0,the surface settlement tends to be stable,and increasing the value of K has little effect on the surface settlement.（3）When the height of piled gravel in front of the cutter head is 2D/3,the pile length L=KD,when the coefficient is 0.50.8,the surface subsidence tends to be stable,and increasing the value of K has little effect on the surface subsidence.Figure [36] Table [3] Ref.[50]...