Expressway projects have a significant investment, long construction period, and many influencing factors. It is necessary to explore the theory and practice of the modernization of expressway construction management and to improve their construction management level further. Based on systematically summarizing the development process and focus of highway modernization, this paper clarifies the concepts and core essentials for the modernization of expressway construction management and simplifies it as the concept of "intelligentization, construction, and quality". It analyzes the connotation of expressway construction management modernization from elements, three-dimensional structure, and modernization system. Based on humanization, professionalization, standardization, intelligentization, technological innovation, and green environmental protection, etc., this paper proposes a modernization system framework for expressway construction management, and forms the corresponding connotation analysis table, and further clarifies the connotation, goal, idea, and implementation key of the modernization of the expressway construction management. The threshold entry and level evaluation of the highway construction management modernization are discussed by the two stages of establishment and evaluation, and following the logical thinking of Connotation/Ideas-Goals-Criteria and Standards, an evaluation index system is proposed based on the practice of Guangdong Province expressway construction management. The research results have reference value for further improving the level of expressway construction management and help to realize the modernization of the expressway system and capacity for governance.
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It can help improve the risk resilience of urban agglomerations to carry out in-depth analysis of the dynamic resilience evolution characteristics of multi-modal transport networks in urban agglomerations during the risk diffusion phase. Based on complex network theory and its extension theory, this study constructed a multi-modal and multi-level transportation network model for urban agglomerations based on road, railway and air networks. It matched node degree and node betweenness with accessibility, and analyzed their static topological characteristics under risk diffusion. Based on the theory of cascading failure dynamics, it considered the initial risk level, risk warning threshold and risk resilience of nodes at different stages, and constructed a risk dynamic diffusion model based on the nodes and connected edge measures affecting risk diffusion. Considering the characteristics of structural and functional changes under risk shocks, the paper constructed a network structural and functional resilience measurement model, and the resilience performance of multi-modal transport networks was represented by their coupling values. Using the multi-modal transport network of the Guan-Zhong Plain urban agglomeration as the research object, the Python Networkx and Matlab network analysis tools were used to simulate and analyze the dynamic resilience evolution of the multi-modal transport network of the urban agglomeration during the risk diffusion phase with respect to different risk diffusion methods, network reliability, redundancy, robustness and node risk handling capacity coefficients. The results show that the model results are consistent with reality. The network resilience can be effectively enhanced by improving network reliability, redundancy, robustness and node risk handling. Compared to the risk diffusion approach based on the node measure, the risk diffusion approach based on the connected edge measure has greater impact on resilience performance, suggesting that the distribution of route hierarchy levels has a greater impact on the resilience performance of multimodal transport networks in urban agglomerations compared to the number of routes.The overall resilience of a multi-modal, multi-level transport network performs better than that of a single transport network.
To achieve the integrated development of transport, economy, and ecological environment quality, it is necessary to identify the core clusters and key nodes properly in urban agglomerations.
In this paper, the Guanzhong Plain urban agglomeration is taken as the research object, and weights are assigned to the functional attractiveness of nodes, radiance, and carbon emission intensity through the entropy method. A modified gravity model based on the multidimensional characteristics of the integrated transport network nodes is constructed to calculate the strength of the spatial connections between districts and counties within the urban agglomeration. Furthermore, a model of spatially linked networks is constructed by combining the spatial structure theory with complex network theory. This model takes the skeleton of the comprehensive transportation network as the main body, the districts and counties as the nodes, and the indicators of transportation network level, functional attractiveness and radiance, and carbon emission correlation intensity as the connected edge weights having multidimensional and multilevel characteristics. Additionally, unnecessary parameter calculations are removed to improve the INFORMAP algorithm by combining the centralities of degree, betweenness, and closeness obtained from the complex network theory. This improved INFORMAP algorithm classifies regional clusters separately in terms of traffic, function, and carbon emissions. The result reflects the strength of the spatial linkages between the districts and counties of the urban agglomeration in different dimensions. Finally, based on the results of regional grouping and the hypergraph theory, we construct a hypergraph network model of ecologically integrated transport networks in urban agglomerations, and key indicators such as neighborhood hyper degree and neighborhood influence entropy are proposed to identify the key nodes of ecologically integrated transport networks in urban agglomerations.
The high-speed railway, motorway, and mainline railway networks of the Guanzhong Plain urban agglomeration were divided into two clusters. The western cluster had a considerably lower frequency of intercity travel than the eastern cluster, and the Xi'an cluster had an increased transport network and frequency of intercity travel. The result of the high-level division of the transport network into clusters was mostly centered on prefecture-level cities. The spatial distribution pattern in terms of functions and carbon emission links had one pole and many cores, with Xi'an at the core. In terms of the relationship between cluster and administrative divisions, some districts and counties had broken through the constraints of higher administrative divisions to form independent groupings. Xi'an and Xianyang were key nodes in the construction of the ecologically integrated transport network of the city cluster. The importance of the nodes in the eastern cluster was found to be greater compared to the western part.
To achieve an integrated development pattern of transport, economy, and ecological environment quality in urban agglomerations, we optimize the layout of the existing transport network, increase the proportion of the low-grade transport network, supplement and connect the high-grade transport network through the articulation role of the low-grade transport network, and create an integrated multilevel transportation network pattern.
The resilience of multimodal transportation networks in urban agglomerations to attacks was analyzed using a network structural resilience assessment model based on complex network theory and resilient city theory which considered the absorbing capacity, buffering ability and recovery ability of the networks. The network resilience was calculated by a space vector modulus. Data for road and railway passenger transport between cities in the Guanzhong Plain urban agglomeration (GZP agglomeration) was used to construct the regional transportation network. The topological characteristics of the multimodal transportation network were then analyzed using the ArcGis and Ucinet tools. Each node's geographical location and transport connections with the surrounding area were used to identify key nodes based on the node importance. Analyses of the effects of attacks on these key nodes in the multimodal transportation network showed that the network had poor buffering ability, especially after failure of the Caijiapo station when the buffer value decreased to 0.388 9. The system had very weak ability to return to the normal state after a site with a large node degree failed. Failures of the general railway station and the high-speed rail station had far greater impacts on the structural resilience than failure of the highway terminals. Analysis of the characteristics of the key nodes led to suggestions for improving the network structure resilience.
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