Research On Calculation Method And Controlling Measures Of Ground Settlement Induced By Subway Shield Tunnelling Construction

With the rapid development of social economy, development and utilization offloor space have been far from meeting the needs of urban development, and how tomake better use of underground space development is to solve the bottleneck of thedevelopment of urban transport priority. Shield adapt its formation, speed, constructionquality assurance, and other significant advantages are widely used in urban subwayconstruction, but in shield tunneling construction process, you can not avoid disturbanceto the surrounding rock mass produced, thereby triggering different levels of soildeformation and ground movement. Therefore, it is necessary to understand shieldconstruction on soil disturbance mechanism and scope of the analysis results and controlthe distribution of the disturbance factors of soil, in order to accurately predict andcontrol surface subsidence in the shield construction phase.In this paper, Nanchang Metro Shield Tunnel project as a background, combinedwith numerical simulation and field measurement methods for predicting grounddeformation caused by shield construction subway tunnel studies, the main researchwork and achievements are：（1）Reviews the development and application of shield tunneling current situationin China, and ground deformation caused by shield tunneling prediction methods weresummarized and concluded, analysis the mechanism of surface subsidence caused by ashield tunneling.（2）FLAC3D finite difference method can simulate EPB shield in water-rich sandyand gravel construction, the results obtained in good agreement with the measuredon-site, can be ground displacement and deformation prediction analysis of the factorsaffecting the actual project.（3）FLAC3D can simulate the use of ground settlement and lateral longitudetunnel shield tunneling ground settlement, which caused by the lateral settlement ofearth surface draw a "V" shape, from the direction of the positive sides of the centertunnel and the settlement diffusion decreases; The vertical settlement of earth surfacewas "S" shaped, shield excavation from a certain distance in front of party performanceuplift, excavation face behind the performance of the settlement and with the excavationdepth increases gradually increased and then stabilized.（4）Shield works with the actual surface subsidence monitoring, in water-richsandy and gravel formations improved ground conditioning by adding bentonite or foam construction, making ground conditioning has good fluidity and sealing of the effects,beneficial to the excavation face remained stable, effective control surface subsidence.