Shield Tunneling Construction Technology For Culvert Of Subway In Xibao Railway Under Water-rich Sand

The civil construction project D4TJSG-17 of xi'an metro line 4(Yuanshuo road station ~ north passenger station interval)crosses the Xibao high-speed railway culvert in the construction process.The stratum is rich in sand texture.In view of the high penetration,high dense sand whole section earth pressure balance shield tunneling of soil pressure is difficult to establish,change of land subsidence,and the main work and research results are as follows:(1)According to the engineering characteristics of the water-rich sand texture layer under the Xi 'an subway,combined with the existing construction experience and the previous construction,this paper puts forward the reconstruction and improvement plan of the full-section water-rich sand stratum soil pressure balance shield system.Based on the working condition of engineering geology characteristics and construction of similar engineering construction section construction experience,it has suggested that the earth pressure balance key parameters through the high-speed rail area construction,made a safe and feasible to wear under the shield of high-speed culverts.(2)Numerical simulation studies were conducted on the settlement characteristics of ground and high iron culverts caused by the construction of the shield under shield in Xi 'an metro line 4.Research shows that under shield construction,the maximum settlement amount of the surface is 2.2mm,while the surface subsidence in the lower part of the culvert culvert is relatively small,with the largest settlement average is about 1.6mm.Therefore the culvert structure has certain restriction effect on the ground.Under normal shield construction,the culvert structure will not cause partial or overall tilt or even damage.(3)The introduction of intelligent building,material deformation monitoring equipment(intelligent monitoring robot),and the earth pressure balance shield intelligent wear high-speed rail culvert under continuous monitoring,which ensures the construction safety of metro in high-speed lines under,and forms an intelligent monitoring and early-warning technology for the construction of important risk sources under the whole subway tunnel.(4)Following the data on the dynamic settlement of the shield construction,the improvement measures of the shield system and the adjustment of the construction parameters of the soil pressure balance shield in the sand layer effectively reduce the excessive deformation of the strata caused by the construction disturbance,the maximum settlement value of surface subsidence caused by the tunneling construction,the accumulated settlement value and the surface uplift value are all in the better control range,and there is no warning phenomenon,and the shield tunneling construction is well controlled.