Construction Schedule Risk Analysis Of Municipal Engineering Based On Fuzzy BN-MPERT

With the advancement of urbanization and the increase of urban functions in China,residents’ demand for public infrastructure within the city is continuously increasing,and the construction volume of municipal engineering is expanding rapidly.Municipal engineering construction generally has the characteristics of tight time,large amount of interface coordination and limited construction site.The slow progress of the municipal engineering will not only cause economic losses for all parties involved,but also affect the normal work and life of the residents even delays the overall planning and layout of the city.Therefore,schedule control is one of the important tasks of municipal engineering project management.In order to achieve the goal of making reasonable progress plan and adopting scientific progress control means to effectively control the construction progress,it is necessary to calculate the planned period of the municipal project and evaluate the progress risk.Taking a typical municipal engineering subway station as an example,and taking how to quantitatively analyze the impact of schedule risk factors on the status of activity duration as a breakthrough point,this paper proposes the fuzzy BN-MPERT that integrates the fuzzy set theory,Bayesian network(BN)and the modified program evaluation and review technique(MPERT)to study the municipal engineering’s planned period and its construction schedule risk.The main contents of the study are as follows:(1)Starting from the seven major risk sources,i.e.owner,contractor,design,supervision,material and equipment,labor,external factors,using document analysis method to identify the risk factors of subway station construction progress,using Delphi method and statistical method to rank them according to the importance score given by experts,screening and determining the risk factors to be considered.(2)Taking the identified risk factors as nodes and determining the causal correlation of nodes according to expertise to complete the BN structure of schedule risk in subway station.Combining the fuzzy sets theory and the defuzzification method,the possible linguistic variables given by experts are transformed into fuzzy probabilities,which are regarded as prior parameters of BN.Based on these,the probability of each state of process duration under the influence of schedule risk factors and their correlation is calculated,and then sensitivity analysis is carried out by reverse reasoning.(3)Calculating the three-time estimated expectation values of each process according to the solution results of BN.Based on this,MPERT is used to quantitatively analyze the corrected value of the subway station project period after considering the influence of the secondary lines on the dominant line,then the completion probability and the progress risk rate are calculated.(4)Taking a subway station project as an example,analyzing the construction process and then using the fuzzy BN-MPERT to achieve progress risk analysis.The research results show that the risk analysis method of metro station schedule taking into account the schedule risk factors and their correlation and the interaction of lines in schedule network diagram is considered reasonable and reliable,it provides technical support for the progress optimization and risk management of municipal engineering.