Analysis Of Stability Of Surrounding Rocks Under Shield Originating

In recent years, with the rapid development of China’s urban subway project, shieldconstruction is applied widely and occupies an important position in urban subway, but theresearch of the shield originating cause surface subsidence is a serious deficiency and theuncertainty range of the longitudinal ends of the shield originating reinforced is a huge risk forits construction. Therefore, Mechanical analysis on longitudinal soil reinforcement at the shieldoriginating and how to determine a reasonable range of the longitudinal reinforcement became aserious problem.First several theories of cemented soil stability for shied tunneling breakthrough, thelongitudinal soil consolidation scope at the shield originating, he analysis of shield driving effecton ground subsidence are introduction briefly in this paper. And then the shield originatingmodel is model of the difference software FLAC3D. The influence different longitudinal andtransverse reinforcement length at shield originating tunneling process exerts upon verticaldisplacement field of soil, the stress field, surface subsidence is introduced in detail,and then thegeneral rule is summarized. With the help of Hefei No.1subway line FanHua road to High-speedRail station field measured results of practical project at the shield originating, thereasonableness of the model and results of numerical simulation in this paper is verified, andresearch was supported by the following conclusions:1)The construction process of the underground tunnel in FanHua road to High-speed Railstation field was simulated. Compared the monitoring date with strata displacement、groundsettlement values obtained by simulating，results of the two curves in a consistent, size fits wasshowed.The actual working condition could be better simulated by the three-dimensional model.2)With the longitudinal soil at the shield originating increased,surface subsidence isSignificantly reduced;With the Lateral soil at the shield originating increased,surface subsidenceis reduced little3)The surface subsidence increases along with the shield segment as close to the surfacemonitoring,and the surface subsidence reduces along with shield segment as close to the surfacemonitoring.when shield cutterhead was away from monitoring stations double shield diameter Inthe process of shield tunneling,The surface subsidence had little been impacted and even couldbe neglected.4)By the simulation analysis of various working conditions,we come to the conclusion thelongitudinal soil of6meters at the shield originating meet the stability in Hefei...