Research On Deformation Characteristics Of Deep Foundation Pit Of A T-shaped Subway Transfer Station In Hefei

The construction of subway network is bound to face many subway station foundation pit excavation.Compared with the conventional subway station,the foundation pit of transfer station often has the characteristics of more complex retaining structure and higher construction risk.The existing subway transfer station foundation pit shape is mostly "ten" or "T" type.Due to the complexity of the shape of the foundation pit of the subway transfer station,the excavation of the foundation pit of the transfer station will have a more complex impact on the surrounding building structure,so it puts forward higher requirements for the support form and construction method of the subway transfer station.Although there are a lot of researches on the deformation law of subway foundation pit engineering,there are few researches on the deep foundation pit engineering near the "T" type transfer station of rainwater box culvert.Therefore,it is of great significance to carry out the research on the deep foundation pit engineering of "T" type transfer station under the above specific conditions.In this paper,the deep foundation pit of Hefei rail transit line 3 and line 5 transfer station(Haitang station)is simulated and analyzed by using Midas/GTS large-scale finite element software.Through the establishment of the overall three-dimensional numerical model of the deep foundation pit of the "T"-shaped transfer station,the deformation characteristics of the foundation pit during the excavation of the foundation pit are studied.The main research contents are as follows:(1)Combined with the project,using the numerical simulation software,this paper analyzes the correlation between the built foundation pit retaining structure and the continued foundation pit retaining structure,the deformation law of retaining structure,the surface settlement law,and the correlation between the surface settlement and the deformation of rainwater tank culvert in the process of stepped excavation of "t" type deep foundation pit;In addition,this paper also studied that under the condition of the original "T" type subway station deep foundation pit enclosure structure unchanged,two new excavation schemes were proposed,and the original excavation scheme was compared through numerical calculations,and finally the optimal excavation Program.(2)Combining the subject engineering,processing and analyzing the deformation and surface settlement of the deep foundation pit of the "T"-shaped transfer station obtained from the on-site monitoring.Study the deformation law of the enclosure structure and the law of ground settlement during the construction of the deep foundation pit of the "T"-shaped transfer station,and compare and analyze the calculation results.(3)Aiming at the rainwater tank culvert installed on the east side of Line 5,this paper uses numerical simulation software to study it,and analyzes the influence of the "T"-shaped foundation pit excavation process on the deformation of the adjacent rainwater tank culvert.In addition,the deformation laws of horizontal and vertical displacements of rainwater tank culverts at different depths and distances are studied.