Research On The Planning And Pre-evaluation Of Underground Expressway

Nowadays, as the traffic grows rapidly, the contradiction between transportation supplyand demand is becoming increasingly conspicuous. Taking use of underground spaceresources to construct underground transportation has become one important way to solve theproblem of urban traffic congestion. The system of underground traffic has been built in manycities abroad, mainly in the form of rail transit, however, the underground expressway is alsoan important direction of development.As an important supplement part of ground transportation, the development ofunderground expressway started very late which is in small scale, and the cost of undergroundexpressway construction is much higher than that of viaduct, meanwhile, the construction ofunderground expressway is unrepeatable because of the destroy of land. Thus, it’s necessaryto do the research on the planning and pre-evaluation before the development. In the course ofplanning, pre-evaluation on underground expressway can not only prove the feasibility, butalso instruct the network layout, so that it will ensure the balance between traffic supply anddemand.At present, there is little research on the planning and pre-evaluation of undergroundexpressway owning to the restriction of research method and related data. On the basis ofurban planning theory, operations research, and theories of traffic flow, this paper focuses onthe planning and pre-evaluation of urban underground expressway network. On the basis ofsumming up the research status at home and abroad, firstly the paper proposes layout methodof point, line and area analysis after determining the entrance combined with thecharacteristics of the underground expressway. Secondly, improves the depot choice model ofunderground expressway and then validates it under capacity restraint. Thirdly, brings forwardunderground expressway share rate model based on Mixed Logit and calibrates the parameterusing specific network. Finally, studies on the method of effect pre-evaluation and verifies theproposed method using the actual case.The study in this paper not only proposes a new direction for urban undergroundexpressway system, the research results will also provide the basis of planning, constructionand management of underground expressway system theoretically, induce traffic engineering field to generate new knowledge and have important theoretical and practical significance inpromoting the sustainable development of urban underground transport system.