Research On Fine Modeling And Layout Application Of General Segment Of Subway Shield Based On BIM Technology

Shield method has the advantages of fast construction speed and little impact on the surrounding environment,and has become the primary method of urban subway construction.General segment is widely used in the shield tunnels,which has a certain wedge shape and can be fitted well with the designed tunnel axis(DTA)by assembling different points.There are still some problems in the construction process,such as difficult selection of general segment points,large deviation of the axis of ring tunnel from the DTA,etc.And the manual deviation correction is inefficient and easy to cause artificial errors.Building information modeling(BIM)technology has powerful informatization and visualization functions,which can effectively assist the selection of segment layout points and ensure the quality of shield tunnels.Combining the advantages of BIM technology to guide the smooth assembly of general segment,has become the focus of general segment layout research.In this paper,aiming at the characteristics of general segment,analytic geometry method and BIM technology are applied to study the layout and location of general segment.The main contents are as follows:(1)Analytic geometry method is used to solve coordinates.For different types of line,circular curve and transition curve used in DTA,setting up coordinate system and establishing equation to solve DTA coordinates under different mileage.According to different assembling forms of general segment,the coordinate system is established to calculate the central position of segment ring at different points,and the coordinate calculation formula is deduced.(2)The least square method and enumeration method are used to select and rectify the general segment.The fitting deviation between the corresponding mileage coordinates on DTA and the coordinates of several trial points is calculated,and the point with the least error is selected.The dynamic correction method is optimized based on the assembly requirements of general segment capping blocks and the principle of staggered joint,and the optimization results are accord with the engineering practice.(3)The general segment adaptive model is established,and the control of assembly point of the model is realized.There are obvious differences among the blocks of general segment.The fine model of general segment is built by the method of whole ring first and then its details,which improves the efficiency and ensures the accuracy of the model.The parameter correlation adaptive segment model is set up to realize the control of the general segment model at each assembly point.(4)Combined with practical engineering cases,DTA is drawn by Civil 3D software,and general segment model of shield tunneling is established according to calculation points.Parametric model can query segment assembly point quickly.Pre-assembly of general segment model can effectively solve the problem of straight joint,it improves the construction efficiency and promotes the development of segment assembly informatization.The main innovation is to establish general segment fine modeling by Revit,and realizing the point position control of the model by setting parameters.The general segment model of the shield section arranged according to the calculation point is established to guide the assembly of the general segment,which provides a reference for the application of BIM technology in the general segment layout of the subway shield.