Research On The Settlement Of City Wall Brought By The Constrction Of Xian Metro Line2

Shield tunnel construction is a main construction method of xi’an subwayconstruction.The construction process produced the ground settlement that causedincreasingly prominentsecurityissues about the surrounding buildings,so,try to controleffectively shield constructionsettlement in order to protect safety of the buildings around the engineering, promote thesubway and tunneldesign in loess area of our country, the level of construction to supplementand perfect the existing design specification.Combine an engineering examples of xi’ an metro second line through ancient city wall,on the basis of scene investigation, through numerical simulation and field monitoring dataanalysis, research city wall and its formation stress, strain change rule on the shield tunnelingconstruction process.First,through calculate the stress of city walls under different sedimentation value andcompared with the physical experimental value, find out the control standard of city wallssettlement (surface maximum subsidence control standard+5~-15mm, local slant not morethan0.001). And focuses on the research and simulation the different operatingconditions,shield tunnelcaused strata subsidence deformation to the influence law of the citywall, through compared take reinforcement and notreinforcement way beforeshield tunnelconstruction, and then put forward the corresponding walls reinforced protection measuresand related suggestions: Strike filling piles in the shield tunnel side can effectively reduce theinfluence of the tunnel excavation on the lateral city wall settlement, and can effectivelyreduce the settling tankinfluence scope, this is an effective reinforcement program. Andverified taking engineering measures that is necessity, reasonableness and validityin theconstruction.