| Expressway construction plays an increasingly important role in national economic and social development.Due to the various factors,large capital,and long cycle involved in highway construction projects,the core factors such as quality,schedule,cost and safety need to be considered in the construction of expressway projects.It is an urgent problem to coordinate and control the relationship among these factors.This paper fully considers the realistic characteristics of expressway construction,and combines modern management system engineering theories and methods to provide theoretical and practical support for the coordinated control of quality,schedule,cost and safety objectives in highway project construction.(1)As for the current situation of the construction of expressway projects and the problems existing in the management,the project management theory,system analysis theory and method are used to build on the multi-objective coordination and control system framework of expressway construction projects.The system framework includes four modules: target module,macro environment,operation mechanism and new technology application.The target module is the research focus and difficulty,including quality,schedule,cost and security.Macro environment,operation mechanism and new technology application are the guarantee and foundation of the system operation.This framework system systematically analyzes and describes many factors involved in the construction of expressway projects and their relationships,laying the foundation for in-depth study of various factors and their mutual relationship,and providing theoretical support for the construction of expressway projects.It also enriches the management theory of highway project construction.(2)The double-layered quality chain of highway project construction is proposed,and the system dynamics quality control model and cost-quality control model of the construction process chain are constructed.Focusing on the construction process,the outer quality chain including decision-making,design,construction,acceptance,operation and maintenance is analyzed.The construction process is subdivided and designed,and the inner quality chain is nested.The causal circuit diagram of the influence factors of construction process quality is established by using system dynamics theory.The feedback coupling relationship between various factors is analyzed.The flow chart of quality control stock of expressway project is drawn.The simulation of the construction process is carried out to identify sensitive variables.As a result,the quality control effect of the construction process is improved.(3)The progress evaluation model of expressway project based on Bayesian network is constructed,and the progress cycle control system of expressway project is proposed.The influencing factors of highway project schedule are divided into environmental impact factors and main control factors,and the Bayesian network evaluation model of environmental impact factors is constructed.The sensitivity analysis of environmental impact factors is carried out.Based on the comprehensive analysis of subjects,objects and elements,and combined with the evaluation results of Bayesian network environmental impact factors,a multi-link highway project schedule control loop control system including environmental impact factor evaluation,main body capability optimization and project schedule control is constructed.Methodological support is provided for the progress control of highway projects.(4)Based on fuzzy association model and earned value method,a two-stage cost prediction control model for expressway project construction is constructed.The complexity and uncertainty factors affecting the construction cost of highway construction are analyzed.The fuzzy correlation knowledge is used to establish the evaluation index of highway cost forecast based on the combination of data statistics and expert scoring.The closeness and fuzzy correlation degree with the sample highway cost are measured,and the fuzzy correlation model of cost prediction is constructed,and the cost estimation of the proposed highway bridge,tunnel /culvert and pavement engineering is carried out.On the basis of this,from the perspective of project performance management,the cost deviation analysis and control of the two factors of highway construction cost and construction period are selected according to the method of choosing fixed time period nodes and setting the detection points,analyzing and controlling the cost deviation of the two elements of highway construction cost and construction period,and putting forward cost management suggestions.(5)A multi-level highway construction safety risk prevention and early warning system including state monitoring,risk assessment and response decision-making is built on.In the state monitoring module,multi-source information sharing,exchange and fusion technologies are used to perform multi-level and multi-faceted information acquisition and fusion optimization for entities and information sources.In the risk assessment module,objective factors and human factors of the cause of the failure of the basic event are analyzed,and the failure probability of each basic event and the probability of occurrence of the top event are calculated by the accident tree analysis method.In the response decision module,the security risk analysis is carried out based on the static and dynamic indicators,and the state prediction and decision response are made according to the environmental conditions and the situation change,which provides experience for highway risk prevention and early warning.(6)Based on the benefit theory and balance theory,a multi-objective coordinated comprehensive evaluation model for highway construction project quality,schedule,cost and safety is constructed.A multi-level coordinated control evaluation index system for quality,schedule,cost and safety is constructed according to the multi-objective characteristics of expressway project construction.The basic benefits,compound benefits and balance index are designed for comprehensive evaluation.The complexity of multi-objective influence is considered.The coordination degree evaluation is divided into two stages.The first stage is the evaluation of the coordination degree of quality,schedule and cost.In the second stage,the quality-schedule-cost is taken as a whole and then added into the safety target to evaluate the coordination degree.The multi-angle comprehensive evaluation of 15 RX high-speed sections is carried out,and countermeasures and suggestions for promoting multi-objective coordination management are proposed. |
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