Application Research Of BIM 4D Technology In Turnout Replacement Construction Of Existing Line

With the rapid development of China’s railroads and the scale of the road network continues to improve,the construction and maintenance tasks of railroad engineering units are becoming increasingly heavy and demanding.In order to fully exploit the railroad transport potential,while solving the contradiction between the construction and maintenance of existing lines and railroad transport production,the railroad corporation proposed a comprehensive maintenance of the mode.At present,the existing line comprehensive maintenance construction of the construction boundary of each parallel operation and the coordination of the scheduling of people,machines and things most of the construction experience,low rate of daylight cash,the traditional two-dimensional existing line construction scheduling management method is difficult to solve the comprehensive maintenance of the construction operations of personnel,equipment(machinery,materials),the environment in time and space conflict problems.Therefore,this paper considers the combination of BIM 4D technology and railroad existing line construction characteristics,the existing line comprehensive maintenance construction management of new methods to try.Existing line comprehensive maintenance skylight is composed of a number of single construction operations in the same point in time parallel operations,to solve the integrated maintenance of space and time conflict problem,first of all to achieve effective construction management of single construction operations based on BIM 4D technology,get the construction risk can be controlled under the conditions of single operations can be compressed time,space,and then through the evaluation of the level of risk of single operations for the overall integrated management to provide Theoretical basis.This paper mainly takes the single construction operation of turnout replacement in the comprehensive maintenance of existing line as an example,through the BIM single open turnout accurate modeling,based on BIM 4D technology to build the existing line in-situ method turnout replacement construction site dynamic arrangement model,the corresponding spatial and temporal optimization,and the risk level evaluation of the single construction operation.The main research contents are as follows:(1)Combing the existing line turnout replacement method and specific construction operation flow,using Revit as the modeling platform,and selecting suitable base family sample files according to the characteristics of turnout components to realize the creation of turnout component family,and some of the components are parametrically modeled.On the basis of establishing the standard component library of turnouts,Dynamo is used for the secondary development of Revit to complete the automatic assembly of turnout model,and Navisworks software platform is used to create the construction task plan of turnout replacement for existing lines and associate it with the completed BIM model of turnouts to form BIM 4D model,which realizes the construction process simulation and visualization of turnout replacement construction for business lines.(2)BIM 4D technology based on the existing line turnout replacement construction site layout dynamic optimization.In the establishment of existing line construction site layout model based on the existing line construction operations between the temporary facilities to minimize the total time consuming material handling and temporary facilities between the relationship between the total and maximize the goal,the establishment of space-time dual objective function,divided into construction phases,the corresponding phase location of the construction facilities as the decision variables,taking into account the space-time constraints and construction risks to build a construction site dynamic layout model,using genetic algorithm The dynamic layout model of the construction site of the constructed existing line is optimally solved.Combined with the single construction of in-situ method turnout replacement at Sanying station on the Baozhong line,the optimized construction site dynamic arrangement reduces the total objective function value by 10.17% compared with the traditional construction site layout of the existing line,proving that the method can reduce the operation time and space in the single construction operation of the existing line by coordinating the scheduling of the time and space involved in man,machine and material,which is essential for solving the subsequent comprehensive existing line construction and maintenance of space-time conflict problems can provide a certain reference value.(3)To summarize and sort out the main risk factors from the five aspects of "personnel,equipment(machinery,materials),method,management and environment" in the single construction operation of turnout replacement on railroad existing lines,establish the construction risk evaluation model,and evaluate and analyze the risk level of single construction operation of turnout replacement on railroad existing lines by using fuzzy comprehensive evaluation method,and get The risk level value of single construction operation of turnout replacement is 4.78,which can provide individual calculation basis for subsequent parallel operation combination mode,determining construction main unit and other construction comprehensive management decisions.