Study On Decision-making Evaluation Guidelines System For HUNAN Expressway Asphalt Pavement Overhaul Timing

With the gradual improvement and development of the transportation industry,the expressways network in Hunan Province is basically established.Expressway maintenance as the precondition for the unblocked-traffic and transportation development;needing to match a properly multi-objective decision-making process which is essentially to seek a best maintenance timing and strategy under the constraints of capital and performance,its process is a multi-objective decision-making.It has not been existing a unified time point standard for decision-making during overhaul engineering in Hunan Province.Decision-making is used to determined by the staff experience which lacks of scientific basis.To solve this problem,utilizing information and field inspection data,in overhauled expressway in Hunan Province,and engineering economic theory to study decision-making time point guidelines system in overhaul expressways.The research contents and conclusions are mainly followed:(1)The affecting factors are analyzed on asphalt pavement overhaul timing decision both from the perspectives of transportation agencies and users.Analyzing results demonstrates that the main affecting factors are pavement performance and economy,followed by pavement structure,traffic flow,expressway safety and so on,then putting forward a evaluation guidelines representing this factors.(2)On a basis of investigating and surveying on the technical condition of existing overhauled expressway sections in Hunan Province and others,the thesis demonstrates an inappropriate phenomenon on the minimum condition requiring overhaul comparing with actual traffic requirements.The acceptable minimum of pavement performance on expressway is determined with mathematical statistics method suitable for Hunan Province.Then the method is given scoring the expressway technical guidelines of overhaul time point.(3)By means of life cycle analysis method discuss the economical efficiency of pavement overhaul and establish the pavement performance prediction model.The evaluation method is put forward of economic guidelines for overhaul timing decision-making and the calculation formula of threshold is derived.The specific thresholds of the guidelines for different pavement structures is determined by studying the maintenance conditions of typical pavement structures in Hunan Province.(4)The thesis study the evaluation guidelines'scoring method in traffic safety and traffic diversion condition,establish the AHP guidelines system model for the asphalt pavement overhaul,and adopt the comprehensive evaluation guidelines for overhaul timing decision.In further,take otsu algorithm to seek the scoring standard for comprehensive evaluation guideline.The adaptability of this method is proved by analysis of case study on the expressway in Hunan Province,and the method are applied to the Lin-chang expressway.The result provide a reference to overhaul engineering.