Numerical Analysis Study On Influence Of Chang Chun Mertro Cross Interchange Transition Station Excavation To Adjacent Tall Buildings

Because the underground construction environment is complex and thesurrounding high-rise buildings are intensive, it is not only necessary to take thesafety of the tunnel excavation itself into consideration, but also to consider theimpact of excavation on nearby buildings in the process of urban subwayconstruction. This paper is based on Changchun Liberation Road metro transferstation project. Professional software like MIDAS/GTS and FLAC3D are appliedin this paper to construct numerical models and then the influence law of subwayexcavation on the deformation of adjacent buildings is analyzed. This papermainly include following researches:(1) The research on different excavation sequences of the main body ofLiberation Road Station;(2) This paper analyzes the risk and Changchun two leading winddirection,basic wind pressure conditions of wind effects on tallbuildings;(3) The research on the impact of different horizontal distance ofChangchun subway excavation and Unicom building.Following conclusions can be obtained from above research:(1) In the research and analysis of different excavation sequence, no matterwhich line is first, differences in the foundation settlement buildings and lateraldisplacement of the pile foundation of buildings are small. It is mainly becausethe distance between buildings and the underground excavation edge is long, theimpact of different excavation sequence on the stability of buildings are basicallythe same. In the Changchun Liberation Road cross tube interchange stationproject, it can’t judge the influence extent of excavation sequence on the Unicombuilding just considering the value of building subsidence and the lateraldisplacement of the pile foundation of buildings. It is suggested to take otherfactors such as construction time limit for a project and the project cost intoconsideration to make reasonable excavation sequence. (2) According to local climate conditions in Changchun, the wind load fromnorthwest and southwest is applied on the Unicom building and the analysisresults show that the wind load has adverse effects on buildings. And in thecomparison analysis of building foundation settlement, the influence of windload from southwest is greater. In the comparison analysis of the lateraldisplacement of the pile foundation of buildings, the influence of wind load fromnorthwest is greater. The result illustrates that the effect of wind load fromdifferent directions has different types of damage on buildings. So it should takereasonable protection measures according to the construction environment inactual projects.(3) In the analysis of influence of the distance between the edge ofexcavation and buildings on structures, when the clearance between buildingsand the edge of excavation is getting smaller, building basal displacement andlateral displacement of the pile foundation have obvious increase. Namely theeffect of underground excavation on the stability of buildings increases with thedecrease of the distance between the underground excavation and buildings.Especially when the distance between buildings and the excavation edge is5m,the settlement difference of monitoring points in northeast corner and southwestcorner of the building is15.7mm. The lateral displacement of the pile foundationof the building is about20mm. These damages to the building are larger, soreinforce and protection measures must be taken to buildings in theconstruction.