This study was conducted in the context of the latest Chinese policy on “double carbon”. First, we obtained building skywell and meteorological data parameters through a site survey and measurements. We applied the PHOENICS software to simulate and analyze the wind environment of a traditional building skywell. Secondly, the outdoor wind environment of typical building skywells could be simulated and evaluated one by one. Finally, using the method of controlling the variables and by combining typical buildings and skywell-scale layouts, the study summarized and compared the wind environment of the skywell under different scale combinations from three aspects: building skywell shape, skywell scale ratio, and skywell door opening. The following conclusions were drawn: (1) Among the four skywell shapes, the wind environment inside of the skywell was best in the HUI shape. (2) The wind environment inside of the skywell was best in the simulated skywell width-to-height ratio D/H values of 0.2–0.6; the AO shape D/H value was equal to 0.3; and the best wind environment in the skywell occurred when the D/H value of the HUI shape was equal to 0.4. (3) The wind environment in the skywell was best in the range of 1–1.5 for the aspect ratio W/L in the HUI-shaped building skywell (when the width-to-height D/H ratio was 0.4). (4) The opening of the door of the residential building had a great impact on the wind environment of the skywell.

This paper studies the shape design strategy of underground atriums in cold regions based on climate adaptability. From the perspective of climate adaptability, by controlling the shape design parameters of the atrium, and taking the light and thermal performance of the underground atrium as the optimization goal, the light and heat performance simulation and multi-objective optimization are constructed. Method, analyzing the effect relationship of various shape parameters on the light and heat environment and exploring the shape scheme of the underground atrium suitable for cold regions. And it is hoped that architects can take into account the quality of the light and heat environment of the underground atrium in architectural design and use space adjustment to improve the awareness of the quality of the light and heat environment of the underground atrium. The simulation results show that the annual PMV thermal comfort time percentage is 20.47%, the heat radiation difference RAD in summer and winter is 21.17 kw∙w/m², and the average percentage of natural lighting is 67.41%.

High-rise developments frequently exert adverse impacts on the outdoor wind environment, leading to a deterioration in the overall quality of urban surroundings and a reduction in the comfort levels of residents. This study systematically investigates typical high-rise settlements in Xuzhou City and proposes optimization strategies to address wind environment issues through an in-depth analysis of building planning parameters. Utilizing Computational Fluid Dynamics (CFD) simulations, the research identifies key wind-related challenges associated with high-rise buildings in representative settlements. The study comprehensively examines the effects of building height, width, orientation, spacing, and layout on the outdoor wind field, progressing from individual building units to clusters. Based on these findings, optimization strategies are formulated and validated through CFD simulations conducted on a representative high-rise settlement in Xuzhou. The results reveal that typical high-rise buildings in Xuzhou exhibit a height of 54 m, a width of 48 m, and an orientation ranging from 15° to 30° southeast. The front-to-rear building spacing is approximately 1.44 times the building height, with an additional 15 m spacing from mountain walls. Optimal wind conditions are achieved with a center-vacant building layout. The optimization of building form, spacing, and orientation substantially improves the outdoor wind environment by alleviating stagnant wind zones and reducing wind pressure differentials between the building fronts and rears, thereby enhancing the comfort of residents. This study provides a valuable reference for the planning and design of high-rise settlements, contributing to an improvement in urban environmental quality and the enhancement of livability.

China’s urban development has entered the stage of urban renewal, transitioning from large-scale incremental construction to stock enhancement and renovation. In response to challenges such as traffic congestion and land-use constraints, urban planning has increasingly prioritized the development of urban underground space (UUS) and urban rail transit (URT). However, disparities in development levels across cities, as well as the fragmented and uncoordinated integration of UUS and URT, remain significant challenges. While existing studies have predominantly examined UUS and URT independently, the interaction between the two has been largely overlooked. In order to supplement this gap, the aim of this study is to construct an integrated measurement framework and quantitatively assess the level of integration between UUS and URT in 38 Chinese cities. We seek to explore the interrelationship between the two, identify the differences in the integration process across cities, and discuss the potential implications for urban planning and policy making. Specifically, this study assembles an integration measurement index framework from three dimensions (UUS, URT, and urban development), quantitatively evaluates the integration level of 38 Chinese cities by using the entropy weighting and VIKOR methods, and summarizes the regionalization characteristics by using K-means clustering. The results of the study show that (1) there is a positive correlation between UUS development and URT construction and the degree of correlation is affected by the level of urban development; (2) the construction of URT is dominant in the integrated system of UUS and URT; (3) the sample cities can be classified according to the characteristics of the integration into the types of developing cities (47.37%), mature cities (21.05%), and underdeveloped cities (31.58%), and there is a clustering effect on the overall spatial distribution.

Between 2019 and 2022, passenger volume on China’s urban rail transit system sharply declined due to strict COVID-19 control measures. On 8 January 2023, China implemented the “Class B infectious disease Class B management” policy, marking a significant shift towards a more relaxed approach to epidemic control. The main objective of this study is to evaluate the immediate and lasting effects of this policy on urban rail transit passenger volume. We used interrupted time series (ITS), combined with quasi-Poisson regression models and counterfactual analysis, to analyze monthly urban rail transit operation data covering the period from January 2021 to June 2024 for 42 cities. Our analysis shows that, relative to the expected trend without any intervention, monthly average passenger volume increased by approximately 101.34% after the policy’s implementation, with significant immediate effects observed in 41 cities and significant lasting effects observed in 33 cities. The study concludes that the “Class B infectious disease Class B management” policy has generally promoted the nationwide recovery of urban rail transit passenger volume, although with significant heterogeneity across cities. This result indicates that the reduction in travel restrictions and the restoration of public safety, resulting from the relaxation of COVID-19 prevention and control measures, contributed to the overall recovery of urban rail transit. This study not only provides innovative methodological insights but also offers valuable guidance on developing more effective urban planning strategies and urban rail transit operational measures in the post-pandemic era.