With the continuous advancement of urbanization, a huge amount of construction and demolition waste (CDW) is generated in large-scaled construction activities, which has aggravated the problem of environmental pollution, waste of resources and destruction of city appearance. In the context of waste-free city, the recycling of CDW can reduce environmental pollution and promote the sustainable development of a city. However, only 20–30% of CDW in the world is recycled, showing a low rate of global CDW utilization. In order to improve the utilization rate, this paper selects construction enterprises and construction material manufacturers as main participants, applies evolutionary game theory to construct an evolutionary game model on the two parties’ decision-making behaviors in CDW recycling, and uses MATLAB to make a numerical simulation. The aim of the model is to analyze the influence of various factors on the parties’ decision-making behavior evolution and propose strategies to promote CDW utilization. The study found that the stable state of the CDW resource utilization system mainly depends on the difference between revenue and costs, the initial strategy, and the strength of the external environment; for the government, a supervision strategy is found to be necessary, and the best supervision level is 0.6. In the early stage of resource utilization of CDW, subsidies to construction material manufacturers should be increased to improve their initial participation; public participation can effectively improve the efficiency of government supervision, and its optimal participation level is greater than or equal to 0.4; under weak supervision, government penalty increases alone cannot prevent construction enterprises from illegally disposing of CDW. Therefore, the greater the difference, the positive the initial strategy, and the stronger the external environment, the more the behavior of the two participants tends to be {participation, use}. The results show that the government should establish effective supervision mechanisms and legal systems, improve supervision hotlines and information platforms, encourage the public to participate in CDW management and supervision, set appropriate rewards and punishments, strengthen supervision and management levels, reduce supervision costs, and ensure the effectiveness of construction management to improve the efficiency of cooperation between construction enterprises and construction material manufacturers.

The urban water supply system environment is becoming more complicated and unpredictable than ever before in the context of global climate change and expanding urbanization. Existing studies have adopted either static or dynamic approaches to assess the resilience of water supply systems without combining the two. Previous literature mostly establishes rigid quantitative metrics for resilience assessment, often without depicting the dynamics and adaptability of system resilience. For example, these studies usually fail to provide a critical point for identifying system resilience. To accurately describe the dynamics and adaptability of water supply system resilience under uncertain scenarios, in this study, we constructed a comprehensive framework based on the qualitative assessment of the input parameters, combining static and dynamic assessment, with the latter playing a dominant role based on the system perspective of pressure–state–influence–response. Taking Qingdao as a case study, we combined this framework with the system resilience theory, and statically assessed the five types of capitals and three attributes of resilience with the capital portfolio approach (CPA). Then, we dynamically assessed the resilience of urban water supply systems and identified critical points with the dynamic socio-technical model coupled with system resilience and the fitting analysis method. The results are as follows: (1) the static assessment results demonstrate an imbalanced development in the levels of the five types of capitals (financial capital, management efficiency, infrastructure, available water resources, and adaptation) and three attributes (robustness, recoverability, and adaptability) in the water supply systems of Qingdao. (2) The dynamic assessment results show that the current resilience trajectory of the water supply systems in Qingdao is that of a city in transition. (3) The fitting analysis shows that robustness (RB) has a linear relationship with resilience, recoverability (RE) has a non-linear relationship with resilience, and the critical points are RB = 0.70 and RE = 1.20. The research findings provide a reference for studying resilience mechanisms, internal attribute relationships, and resilience enhancement measures of urban water supply systems.

As the basic support of regional economic and social development, land transportation is one of the important engines to promote regional development, and its construction and improvement will have an important impact on the regional economic pattern. Based on the road network of Shandong Province, China, in 2020, according to the Medium and Long-term Development Plan of Comprehensive Transportation Network of Shandong Province (2018–2035), this paper uses the GIS network analysis method, weighted average travel time, modified gravity model and other methods to study the land traffic accessibility and economic relation intensity of prefecture-level cities in Shandong Province, China, in 2020 and 2035. The results show that the distribution of land traffic accessibility in Shandong Province, China, shows a certain regional main road pointing characteristic in 2020, and the urban accessibility level gradually decreases along the Beijing–Shanghai high-speed railway and Jinan-Qingdao high-speed railway to the periphery. In 2035, the land traffic accessibility of Shandong Province, China, will be more spatially distributed as “concentric circles”. From 2020 to 2035, the urban land traffic accessibility and the balance of economic contact in Shandong Province, China, will be improved significantly. The research results can provide a theoretical reference for optimizing the traffic network pattern and promoting urban economic contact in Shandong Province, China.

With the continuous advancement of urbanization, a huge amount of construction waste is generated in large-scale construction activities, which has aggravated the problems of environmental pollution, waste of resources and destruction of city appearance. Construction waste recycling can effectively solve these problems. However, the recycling rate of construction waste is low in China. Therefore, this paper, firstly through the way of literature analysis and questionnaire investigation, analyzes the factors that influence construction waste resource utilization, determines the key influence factors and the stakeholders in the process of construction waste resource utilization, and uses social network analysis method to identify core stakeholders. On this basis, this paper selects construction enterprises and recycling enterprises as the game subjects, and the government and the public as the external environment to explore the influence of the external environment on the cooperation behavior of the two stakeholders, and uses Matlab simulation to analyze the influence of external variables on the decision-making behavior evolution of the two stakeholders. The research results show that the government, construction enterprises, recycling enterprises and the public are the four core stakeholders of the construction waste recycling system, which have the power to control the information transmission among other stakeholders and play a great supporting role in the smooth implementation of the construction waste recycling project. Among them, the construction enterprise and recycling enterprise are the construction waste recycling system’s two stakeholders playing the pivotal role, and the government and the public are the external environment of the construction waste recycling system’s incentive and regulatory effect. The difference between the benefits and costs of the two stakeholders and the effect intensity of the external environment determines the stable state of the system, that is, the stronger the effect of the external environment and the larger the difference, the more the behavior of the two tends toward the recycling, on-site recycling strategy. Government penalties and rewards can effectively reduce the illegal dumping of construction waste, while excessive penalties and rewards have limitations in controlling illegal dumping. Public participation can effectively improve the efficiency of government supervision. The research results help to deeply understand the behavior, needs and cooperation of stakeholders in the construction waste recycling market, improve the efficiency of cooperation between construction enterprises and recycling enterprises, and provide management inspiration for the construction waste recycling practice.

With global warming and the frequent occurrence of extreme weather, damage to urban rail transit systems and casualties caused by rainstorm disasters have increased significantly and are becoming more serious. This research developed a network model for the evolution of operational risk in URT systems under rainstorm scenarios that can cause 35 typical accidents. Furthermore, we also investigated the evolution mechanism and devised improvement strategies. Through the network, combined with the complex network theory, the study explored the critical risks and the extent of their impact on the network and proposed optimized strategies to avoid these critical risks. The results show that risk nodes such as R1, R4, R18, and R21 have the most significant impact on the evolution network, both in static and dynamic networks, indicating that station flooding, train stoppage, heavy rainfall, and ponding are the most critical risks to guard against. Gauging the evolution of operational risks in urban rail transit systems and adopting reasonable avoidance measures in this research can effectively improve resilience to rainstorm disasters and the level of operational safety, which can contribute to the sustainable development of transport infrastructure.