Research On Layout Optimization Of Expressway Network In Hunan Province

Expressway network is one of the important infrastructure of a country,and it is an important link of social and economic circulation.With the rapid development of the economy,the traffic demand has increased sharply,so that the construction shortage of transportation infrastructure still exits in some areas,which generates a prominent bottleneck effect to the whole network.From the perspective of the domestic existing road traffic network layout and traffic total mileage,the main reason for this bottleneck is that the coverage of the expressway network is relatively low,which can not be matched with the local social and economic development,and the speed of infrastructure construction and social economic change is unmatched,so that the layout of expressway network in some regions is unreasonably.In addition,the environmental carrying capacity has been ignored for a long time during the expressway network layout.Therefore,there is no doubt that a new thought of network layout must be adopted to remould the existing highway network,which is very necessary and meaningful to satisfy the economy develop demand and the social harmony and environmental friendly.The expressway network of Hunan province was chosen as the research object.First of all,combined with the current situation,the existing expressway network layout still has the problems that the main skeleton is not perfect,the layout is not balanced,and the connectivity is not high.The layout theory and design methods of expressway network plan were summarized at the same time.Through the comparison and analysis of the applicable scope and application effect of the common methods of expressway network layout,in view of the existing problems of expressway,the method of optimizing the layout of expressway network in Hunan province was determined by using the influence relation between social and economic development and the scale of expressway network;Then from expressway network's regional economic connection degree and the overall connectivity of expressway network,a two target regional expressway layout planning model had been established,the often neglected environmental factors were considered at the same time,and the environmental factors and regional planning total construction funds were taken as constraints,the macroeconomic characteristics of the nodes,namely,the regional economic connection as the optimization goal,was adopted in this thesis.At the same time,node important degree was introduced as a regional economic connection degree of some important parameters,and the model was solved by genetic algorithm;Finally,the case study of the expressway in Hunan Province was taken as an example to analyze the model,the idea of a combination of theory and practice was adopted,and the status data was substituted into the model calculation.Through the model calculation,the Hunan expressway network in the target year had been obtained,and combining with present situation analysis,the validity and practicality of the model had been verified.The above model has some explorations in the regional highway network layout,which has certain reference value to the regional highway network layout optimization.