Study On Excavation Process And Numerical Simulation Analysis Of Deep Foundation Pit In Metro Station

With the rapid development of China's economy,the above-ground space in large and medium-sized cities such as Wuhan has become the scarcest resource.Therefore,large and medium-sized cities are making every effort to build underground rail transit projects,and accordingly,there will be a large number of geotechnical problems.In the process of construction,accurately predict and effectively control the deformation of large foundation pit and eliminate major safety hidden dangers has become a very important engineering significance in the construction of deep foundation pit in subway station.Based on the background of the deep foundation pit of Zhongnan Hospital Metro Station of Wuhan Rail Transit Line 8,this thesis discusses the deformation monitoring law of the construction site of the deep foundation pit engineering,and discusses the influence of the internal support system on the deformation of the foundation pit in the process of foundation pit excavation.In this thesis,the monitoring data of foundation pit construction are analyzed at first.The results show that with the continuous excavation of deep foundation pit engineering,the horizontal displacement of enclosure structure is distributed in the shape of "bow",small at both ends and large in the middle.With the increase of the distance from the edge of the foundation pit,the surface settlement deformation shows a downward concave distribution,the maximum uplift of the bottom of the foundation pit appears in the middle of the bottom of the foundation pit,and the axial force of steel support increases and fluctuates at the same time.The settlement of the buildings adjacent to the foundation pit is also increasing as a whole,and it is not until the foundation pit excavation is completed that it tends to be stable gradually.On the basis of verifying the simulation of foundation pit deformation by FLAC3 D software,the influence of internal bracing on foundation pit deformation is discussed.The calculation shows that the use of internal braces with large stiffness,reducing the spacing of internal braces and increasing the number of internal braces can effectively restrain the deformation of foundation pit and ensure the safety and stability of foundation pit excavation.