Research On The Regional Highway Network Layout Optimization Model Based On Combination Optimization And Bi-level Planning

In order to effectively solve the contradictions between supply and need of Highway transportation and to avoid wasting construction sources and road facilities, it is necessary to set down scientific and systematic highway network planning. To improve the highway network planning theory and guide practical construction, is the precise and foundation of developing our Highway transportation.As the demand to highway network planning continuously increase, it is especially imperious to deep study highway network planning theory. The main contents of this thesis include:Firstly, the problems which exist in the present highway network grade structure optimization model are analyzed, through applying new objectives, the persent goal programming model is improved, and the rationality of the improved model is analyzed through example of northeast district highway network grade structure optimization.Secondly, the principle of choosing highway network nodes and node hierarchy division methods are summarized. Through considering nodes' transportation level and distribution of network traffic demand between nodes, put forward traffic volume of passenger and freight as the important index of degree of importance of node, this paper respectively improved the degree of importance model of node and segment.Then, this paper established highway network layout combined optimization model and bi-level planning model which are respectively fit for national level highway network and provincial or urban level highway network, for removing the flaw of without establishing layout optimization model according to the hierarchy of highway network. The rationality of models is analyzed through examples.Lastly, applying respectively lineariyt weighing and summing method and multiply-divide method, the highway network layout combined optimization model and bi-level planning model is converted into single objective optimization model. Geneitc Algorithms is applied to highway network layout optimization problem in this paper, which overcomes the limitation that general algorithm are difficult to solve large scale optimization problem.