Construction Impact Analysis Of Road Underpassing High Speed Railway Bridge Based On BIM And Numerical Simulation

The construction process of the underpass structure has become an important factor affecting the operational safety of high-speed railroads,but the existing research lacks a comprehensive and effective evaluation system for the deformation characteristics of the proximity section of high-speed railroad bridges considering the cross-influence effects among the influencing factors.Based on the influence of roadbed construction in the proximity section of the pier of Ganan Avenue underpassing Gangshen high-speed railway bridge,the deformation of the proximity section of the high-speed railway bridge under different proximity distance,roadbed excavation coefficient,roadbed filling coefficient and construction method are compared and analyzed to sort out the primary and secondary relationships among the factors causing the deformation of the pier of the high-speed railway bridge due to the roadbed underpassing construction,and consider the joint influence effect of multiple factors on the deformation,the proximity project The sensitivity of the impact factors was summarized,and a set of safety risk control methods was provided for similar construction projects.The following works were carried out specifically.(1)Combined with the relevant design specifications and maintenance rules,the deformation control standards of the existing bridge piers in the proximity section were set,and the limit values,alert values and warning values were classified.Midas GTS/NX was used to simulate and test the deformation of bridge piers after roadbed construction,and the results showed that the deformation of the bridge piers and the bending angle of the girder end of the proximity section were within the warning values.(2)Establish the data interaction bridge between Revit and Midas GTS/NX through "Midas Link for Revit Structure" interface and "Send Model to midas Gen" plug-in.The UI interface is developed for Revit to receive structural analysis results through Revit API interface using C# language,which solves the problem of digital modeling of finite element software and structural analysis function deficiency of BIM,and verifies the efficiency of digital modeling of finite element model based on data interaction interface and the practicality of structural analysis results receiving plug-in with engineering examples.(3)For the problem of optimizing the construction method comparison of roadbed construction in the near section of underpassing high speed railway bridge,an objective and quantifiable comprehensive evaluation index system of underpassing project based on structural deformation,internal force change and economic index is constructed,and an evaluation method of road underpassing high speed railway bridge construction method based on AHP-CRITIC and TOPSIS is proposed.As shown by the example analysis,the method has good effect in dealing with the problem of complexity of influencing factors and ambiguity of evaluation criteria in the evaluation of underpass projects.(4)The single-factor comparison test was designed with the proximity distance,roadbed excavation depth and roadbed filling width as variables,and the influence law of the change of each factor on the deformation of the existing structure was analyzed.The case analysis shows that: the proximity distance in the range of [0,+2m] can ensure that the top deformation of the three piers within the limit,the excavation depth can not exceed 2.58 m,and the filling width can not exceed 37.35 m.(5)A significance analysis test was designed by combining four influencing factors of proximity distance,excavation depth,fill width and construction method on the existing high speed railway bridge,and the sensitivity of the influencing factors of this proximity project was summarized by law.The results show that: the construction method of the new roadbed has a particularly significant effect on the disturbance of the x-direction of the existing high-speed railway bridge pier;the proximity distance and the filling width have a particularly significant effect on the disturbance of the y-direction of the bridge pier;the excavation depth has a particularly significant effect on the disturbance of the z-direction of the bridge pier,and the corresponding influencing factors can be changed if the deformation degree of the bridge pier in a certain direction needs to be adjusted.