Research On Spatial Network Growth And Accessibility Of China’s High-speed Rail Network

China’s high-speed rail (HSR) network is entering a stage of sustainable development. More and more cities will feel the effects of "space-time shrinking" derived by the reduced travel time. There are serveral chanllenges to understand and evaluate the whole network effects of HSR network including:1) how to evaluate the accessibity of so large newly built high-speed rail in China?2) how to deploy the high-speed train service among the spatial distributed cities and optimize the implementation of the entire system?3) how to estimate the inner-city spatial accessibility of the high-speed rail station by means of aggregating the system accessibility and system-facilited access of the public transport system?There are some disadvatedges on recent methods and techniques to solve the avobe chanllenges:1) there is no sufficient systematical study on the network representation mapping to different functions for transportation network;2) there is no sufficient understand the complexity of railway network with spatial embedding features as well as it’s evovlment although the recent significant developed complex system offers a special perspective to understand transportation network;3) there’s no model to evaluate the spatial accessibility of railway station through the transfer by inter-city public transport system from/to the destination. Because the previous studies on public transport accessibility only refer to system accessibility without taking system-facilited access of the public transport system yet.Aiming to solove these problems and fill the gaps, focusing the network representation, accessibility at national and city scope, and spatial network growth of the abstracted high-speed train service, the thesis is mainly composed of the contents in the following five parts:1. The background and motivation in this thesis are introduced and discussed in the first part. After reviewing the recent different perspectives on transportation network researches on macro and micro levels, the objectives and main contents are listed clearly.2. Detailed literature reviews on spatial network science related to the studies in this thesis are summarized. Serveral previous case studies offer the fundamental theories and methods for this study, including small world network and scale-free network in sptial embedding systems, representation for transportation with diverse functions, complex network techonogy for transportation network, accessibility analysis for transportation system on national and/or city scope and its applications.3. Besed on the complex network theory and techonology to sduty the evolvement of high-speed rail network. The high-speed rail organization network is represented by a P-space graph in which the node is the city and a link exsits between a pair of nodes only if they can be reached from each other without changing trains. Therefore, the high-speed train service between real-world cities is abstracted as the adjacent relationship between nodes in P-space graph. Based on the proposed mechanism, a spatial growth model is developed to simulate the extra links (named "shortcuts") addition process on the underlying topology. Cities located on the same PDL are considered to be connected with each other. Thus, adding an extra link is in essence deploying a through HST service between two cities located on different PDLs. The spatial growth of CHRN therefore evolves as a function of time which would be rather crucial to be quantitatively measured. To place extra links as the expansion of CHRN, an attachment probability, associated with degrees of target pair of nodes and geographical distance between them, is proposed to describe the idiosyncrasy of the added links. Through computer simulation, it is feasible to predict not only the potential changes in structural characteristics of CHRN but also the operation pattern evolution of HST services, which will provide monumental guidance in shaping the large-scale passenger transport network in the future.4. An accessibility analysis to evaluate the impacts of China’s HSR network is described at the macroscopic level. Accessibility quantification and spatial distribution analysis for the study cities are performed on the Geographical Information System (GIS) platform. Accessibilities associated with varying availabilities of HSR, conventional rail, and airline are estimated and compared by the accessibility indicators from different conceptualizations and perspectives. What’s more important, using the contrast analysis to find the relationship between the variation of accessibility with the changes of the transport network structure.5. An aggregated three-step floating catchment area model is poposed to calculate the spatial accessibility of high-speed rail station by the transfer with subway system and quantitive the access to high-speed rail station of the population within different districts. This model expands the previous methods on the accessibility analysis of the inter-city public transport system, taking into account not only the system accessibility of people access to subway system, but also the system-facilated accessibility of the subway network.