Study On Construction Mechanics Transformation Of Main Structure Of Pile-Beam-Arch Method Of Subway Station

The existing surface traffic can no longer afford the travel needs of citizens.To cope with this problem,large and medium-sized cities begin to construct the subway.And the construction of station is a significant part of underground construction.Now there are roughly three methods in the construction of stations.The PBA(Pile-Beam-Arc)method is a kind of shallow tunneling method.It is widely applied in the construction of metro stations because of its advantages such as no hindrance to existing traffic,strong adaptability,small surface settlement and so on.However,the construction procedure of this method is more complex,and many mechanical transformations are involved in the construction.At the same time,the steel pipe column bears the main construction load in the whole construction process,once its bearing capacity is insufficient,it will cause collapse,resulting in serious safety accidents.In this paper,based on the background of the single-layer four-guide PBA method in Harbin Metro Line 2 Shengzhengfu station,the numerical model of the single-layer four-guide PBA method is established by numerical simulation software Midas GTS NX.Combined with the surface settlement data and pile top measured data,the stratum deformation law of PBA method,the stress change law of pile-beam-arch structure,the mechanical transformation phenomenon of pile-beam-arch structure,and the influence of different construction sequence on steel pipe columns are analyzed.Here is my main research content:1.The model of PBA method is set up by Midas GTS NX,while combined with the surface settlement data,the influence of PBA method on the stratum in different construction stages is analyzed.2.Through analyzing the stress change law of the main structure of the station in different construction stages,the stress surge stage of the PBA method,the stress peak value of the main structure and the weakness are obtained.3.Through the analysis of the law of formation deformation and stress change of the PBA method,the key working procedure of the PBA method is obtained,and the mechanical transformation phenomenon of each bearing member in the key process is analyzed,and the mechanical conversion process and times in the key process are summarized.4.By comparing the displacement and stress changes of the steel pipe column in the key procedure under the three models which set up by Midas GTS NX,the construction process with the least influence on the steel pipe column is obtained.