Research On The Reliability Of Road Network In Mountain Disaster Areas In Southwest China

With the rapid development of urbanization in the southwest mountainous region,the increasingly complex and diversified highway system has become vital infrastructure in the southwest mountainous region,playing a key role in economic development and emergency refuge.However,as human activities intensify in the complex natural environment of the southwestern mountain areas,natural disasters and secondary disasters have occurred more frequently,causing more and more serious damage to the mountainous disaster areas,and then problems such as the weak ability to deal with sudden disasters,weak system connectivity,emphasis on individual construction rather than cooperation and cooperation have been exposed in the southwest mountain disaster regional highway system.Thus,this thesis takes the Wenchuan Earthquake disaster area,a typical area in the southwest mountain disaster areas as the research target,combines the functions of the road network in the mountain disaster areas to meet the needs,and aims to refine the mechanism planning of the mountain road system to respond to disasters,and condenses the scientific questions to be "the law of reliability of highway networks in mountain disaster areas".To present the changing characteristics of the network,methods such as complex networks and computer simulations are in the cross application to analyze and contrast three stages and three levels and features of reliability laws are summarized.Finally,the real system is returned to formulate scientific and reasonable emergency strategies as well as the management plan,improving the reliability service capability of the road network in mountain disaster areas.First of all,this thesis clarifies the research connotation of mountain road network reliability,makes a summary of three practical problems in the southwest mountain disaster areas through systematic literature review and investigation analysis,then analyzes the typicality of the research target area,summarize the scientific questions,and establishes a research program oriented on the "reliability of highway network in mountainous disaster areas in southwest China",namely "scientific questions-a target area-three stages(ten models)-three levels(eight indicators)".Based on vital signs of humans and rescue time,three stages are divided into pre-earthquake,golden rescue stage,and comprehensive search and rescue,and then all together10 time nodes are marked,which are the basis for a road network model of 10 periods.The model determines the eight calculation and analysis indexes which represent the network reliability from three levels,that is the whole,the part,and the individual,laying the foundation for the calculation and analysis of the failure and recovery characteristics of the entire process before and after the road network disaster.Secondly,complex network analysis,computer simulation analysis,and other quantitative analysis methods are cross-applied to analyze the reliability of the road network in the severely affected areas of the Wenchuan Earthquake based on three stages and three levels.The changes of the eight indicators of the road network before and after the disaster are analyzed from the whole,the part,and the individual,and the analysis and evaluation based on the calculation results shows that:(1)the reliability of the road network in the mountain disaster areas is affected by multiple performances.(2)the road network in the research target area is random and fails to demonstrate the scale-free characteristics.(3)the road network has a long absorption and adaptation period after the disaster and can last until the recovery period.(4)the road network accelerates the adaptation and recovery process by restoring some attribute road sections.Finally,according to the calculation and analysis results,the characteristics of reliability laws of the network road is summarized from the whole,the part,and the individual:(1)for the overall analysis,there are some risk areas in the road system,which leads to higher vulnerability;different types of critical road sections exist in the highway system and affect the robustness of the system;highway system elastic performance changes show different stages after the earthquake;the road system network structure is incomplete and poorly balanced.(2)for the part analysis,the regions with high local stability are scattered and not systematic;nodes with high K cores and high aggregation coefficients can effectively improve local stability.(3)for the individual analysis,the presence of road sections in specific areas can improve the resilience of the post-disaster road network;road sections that affect resilience change with time and are adjacent to the original road sections.Thus,research on planning optimization strategies is proposed,starting from two aspects.The one is to propose network optimization suggestions from five aspects of network,vulnerability,balance,robustness,resilience,and stability;the other is on the basis of the recommendations of the material morphology planning in the extremely severely affected areas of the Wenchuan Earthquake,based on the reliability law,combined with network optimization recommendations,to make recommendations on the material morphology planning of the research target area.The innovation lies in that this thesis selects a cross-domain urban and rural planning and complex network research field,and carries out extensive research on the southwest mountain disaster areas,providing insights for the subsequent transportation research on the areas;the whole process simulates the catastrophic process of the highway system in the severely affected areas of the Wenchuan Earthquake,which can be the reference for the subsequent research on that area,and the characteristics of the law obtained from the research also have some practical significance to guide the implementation of the actual project.