System Dynamics Analysis Of Security Risk Of Subway Construction Based On The Perspective Of Schedule

As our country enters the peak period of urban subway construction, frequent construction safety accidents bring serious challenges to the subway project management. Safety risk management is the important content of project management. It throughout the whole process of project management, including plan stage, construction stage and operation stage. Based on the accident statistics, the current academic research and national conditions, the risk management of construction stage has its significant academic and application value. This article adopts system dynamics method, trying to identify and evaluate construction safety risk of subway project.During the risk identification phrase, based on a lot of theoretical research, literature research,case analysis and current standard, four categories of risk factors affecting the safety of subway construction are classified. They are environmental factors, management factors, technical factors and factors of materials and equipment. Based on the risk factors, the system dynamics model of safety risk identification is established. A detailed analysis of causes and results is implemented as well as the feedback loop. The tree graphs show the risk transmission path intuitively. By analyzing the polarity of the feedback loop, the system is a regulated feedback loop. Negative feedback loops are the key point of dynamic risk management. During the risk assessment phase,turn the causality graph into stock flow graph. Combined with the project data of actual subway construction case, define the variable parameters and system equations. Through the simulation research, the change trend of safety and schedule risk level obtained. Hiring additional labor,increasing working hours and working strength are frequently used for reducing the schedule gap.Take it as the starting point, simulating six programs of different weights of these three variables.Based on the simulation results, the author put forward strategies for managers' strategy selection under different project objectives.Compared with the existing related research results, this article's innovation point lies in the selection of research perspectives and research methods. This article selects the perspective of security and schedule. It breaks through the long-term separate of them during the existing research and management practice. Compared to traditional project management method, the system dynamics has a significant applicability of subway project, which is a typical large complex nonlinear system.