Research On Modeling And Simulation Of Highway Engineering Project Duration Based On PERT-SD Hybrid System

As ourcountries high speed development of traffic construction undertaking and growing,the number of highway construction scale is expanding quickly.Due to the complexity of road engineering the external environment,difficult construction conditions,participants level is uneven,such as increasing the uncertainty of highway construction,lead to the construction schedule control risk is more and more big.And time limit for a project can be completed on time is of great significance,if blindly take time limit for a project,not only can increase the cost of investment,and may cause safety accidents.First of all,analyzing the deficiency of the traditional schedule management method,on the basis of the present status of road construction,combining with the characteristics of road construction in order to make clear the problem of modeling need to be resolved,then to determine the significance,purpose and the boundary of the model.Secondly,on the basis of the existing cases of engineering,establishing a Pert network plan,and ACTIM heuristic algorithm is used to identify the key chain,and thus the resource constraint into consideration,considering the resource constraints of the construction network diagram.Again,through heuristic recognition algorithm,designing the construction process of highway construction activity in the process of sorting,to get a different set of process activities.To establish a process dependency table function,so as to realize the key chain and the combination of system dynamics.Finally,the selection completed highway construction process in Cheng Du as the research object,through to the already collected the data for processing,and in the reading of vast amount of literature on the basis of the processing parameters in the model,the variables and equations of the model,combined with the actual situation of construction project is established time limit control subsystem,subsystem and resource subsystem,construction process and set up process dependency table function into the system dynamics in the system,which was set up based on the critical chain-system dynamics model of discrete and continuous mixing system.Through the analysis of contact between each subsystem,establishing causality diagram and the feedback loop,and the application of system dynamics VENSIM software for simulation,the hybrid model should be to the actual construction project to the schedule management control simulation analysis,simulation results shows that with the fit of the actual project is very high.In this paper,based on different strategies to dynamic analysis and evaluation of the schedule change,for highway construction progress to realize the effective management,shows the rationality and feasibility of the model,thus effective guidance in terms of actual construction.