Research On Buffer Setting And Monitoring In Schedule Management Of JC Rail Transit Project

Urban rail transit provides great convenience for people s travel,which not only greatly alleviates the traffic pressure on the urban road surface,but also achieves a good energy saving and emission reduction effect.With the development of urbanization,especially the population density of first-and second-tier cities has increased,which has brought great pressure to the urban road transportation system,and also provided unprecedented opportunities for urban rail transit.Some third-tier cities have also begun planning to start construction and start building their own urban rail transit.At present,urban rail transit is mainly based on subway and light rail systems.The subway system needs to carry out a large number of underground tunnel construction in the prosperous areas of the city and the main roads.However,the underground construction not only greatly increased the project construction cost,but also caused long-term adverse effects on the existing urban road traffic,resulting in unnecessary time costs,which puts extremely high requirements on the progress management of urban rail transit projects.And challenges.The project schedule management method has formed a variety of classic methods after long-term development.From the earliest Gantt chart method to the later critical path method and plan review technology,it has been widely used as a project schedule management method in practical projects.With the continuous improvement of project quality standards,the complexity of the process is increasing,and the uncertainties facing project schedule management are also increasing.Traditional project schedule management methods need to consider the impact of various uncertain factors,such as conflicts between resources such as manpower and material resources,uncertainty of project activity duration,and project activity quality.In 1997,Dr.Goldratt published the management book "Critical Chain",introduced the theory of constraints into the field of project management,and proposed a method for managing the progress of critical chain projects.The critical chain method is to use the critical path in the project network plan.And by shortening the duration of each activity on the critical path to achieve control and shorten the total project time,and then through the set buffer to absorb the uncertainty in the project.The introduction of the critical chain method has pushed the project schedule management theory to a new height,attracting a large number of scholars to compete for research,and related academic achievements have been widely used and actual project management,and achieved good results.In order to solve the pain points and difficulties in the management of existing urban rail transit projects,based on the theoretical basis of the critical chain method,this paper proposes a more effective critical chain project schedule management method that is more suitable for the actual situation of rail transit projects.In order to reflect the effectiveness and superiority of this method,this paper takes the JC rail transit PO project as an example,carries out empirical research,and compares and analyzes the traditional project schedule management method.First of all,this paper analyzes the current situation of JC company project schedule management and the limitations of traditional project schedule management methods.Then,in order to solve the limitations of the above methods,the following two major studies are carried out:In the first part,based on the complexity of the urban rail transit project activities and the characteristics of the construction difficulty,the project activity period is estimated in the form of interval numbers,and the construction is based on The critical chain model of the network diagram of the interval number constraint period,the critical chain is identified according to the project completion limit period,and then the buffer is set according to the project activity time parameter;the second part takes into account the pain points of the urban rail transit project management,and the project resources are tight.Three indicators of degree,environmental uncertainty and activity importance are used to describe the risk coefficient of urban rail transit project activities,and the project activity monitoring trigger threshold is set to monitor the project activity of high risk coefficient,and the third level for buffer monitoring the sub-method is optimized to give the steps of dynamic monitoring of the buffer.Finally,an example analysis of project schedule management was carried out for JC PO rail transit project.First,in the early stage of the project,estimate the interval number of the PO project activity period,draw the project network plan map,and identify the critical chain of the PO project and set the buffer according to the interval number critical chain model proposed in this paper.Secondly,during the project construction period,according to the risk factor of the project activity proposed in this paper,the construction progress of the project activity with high risk coefficient is mainly monitored,and then the buffer consumption margin is monitored according to the buffer dynamic monitoring step proposed in this paper until End of the project.Finally,the results are compared with the results of the project schedule management method using traditional critical paths.The research results prove that the method is more suitable for the actual situation of the project,and in the case of controlling the total project duration,the problems of project rush and buffer monitoring error warning signals are reduced,which has important practical application value in project schedule management.