Research On Risk Management Of Urban Underground Utility Tunnel Project Under PPP Mode Based On System Dynamics

Utility tunnel projects often have the characteristics of large scale and high capital requirements.In order to ease the financial pressure,government departments usually adopt the PPP model to carry out the construction of utility tunnel.The PPP model can effectively relieve the financial pressure,and at the same time,it can also give full play to the construction and management experience of the social capital side and improve the construction quality and operation and maintenance performance of the pipeline project.However,China’s PPP model is still in the exploratory phase,and the promotion time of utility tunnel projects is shorter.Utility tunnel itself has high project costs and investment,and the charging mechanism and the mechanism about investment return is not yet clear.In addition,the entanglement of interest among various stakeholders makes utility tunnel PPP projects face more risks and affect the smooth progress of the project.The purpose of this paper is to identify and evaluate the key risk factors that affect the success of integrated pipeline PPP projects,and to provide basis for formulating corresponding countermeasures so as to ensure the smooth progress of the project.The research content of this article includes the following aspects:(1)Risk identification of integrated pipeline PPP projects.The literature research method is used to sort out the risk of PPP projects and the risk of integrated pipeline projects.The initial risk identification table of urban underground integrated pipeline PPP projects is summarized.Taking cost,schedule,quality,safety and project sustainability as the success criteria of integrated pipeline PPP projects,the path of the impact of each risk factor on each standard is analyzed.Considering the correlation between risk factors,a causal feedback diagram of risk in integrated pipeline PPP projects is built.Based on the risk causal feedback diagram,we further identify the risk of integrated pipeline PPP projects.(2)Based on the risk causal feedback diagram,we draw the risk flow chart.Based on the G1 method,each risk factor is empowered,the risk flow chart equation is worked out,and the risk quantitative evaluation system dynamics model of integrated pipeline PPP projects is constructed.Taking an actual engineering project as an example,Vensim,a system dynamics software,is used to evaluate the the target risk level of the project,and sensitivity analysis methods are used to analyze the key risk factors that affect the realization of each target.(3)Risk response and control.Based on the case project,corresponding risk control strategies are formulated according to the results of risk assessment,and its control ideas are applied to the model.Furthermore,the best risk strategy is selected by observing the results of risk changes,which provides a more effective method for risk control strategies decision of integrated pipeline PPP projects.