Abstract:In the underground space development of residential areas, outdoor thermal environments at the pedestrian level greatly depend on the ground greening configuration, which is in turn affected by the overburden thickness of the underground space (OTUS). However, few studies have considered the effects of OTUS on the ground greening configuration and the further effects of the ground greening configuration on the outdoor thermal environment. This study aimed to provide insights into the design of OTUS for improving outdoor thermal environments. Two residential areas with row and enclosed layouts in Nanjing, China, were numerically studied using the computational fluid dynamics (CFD) simulation software ENVI-met. Outdoor thermal environments in the two residential areas, which had the same greening coverage rate, were simulated under different OTUSs and ground green configurations. The results indicate that to create a comfortable outdoor thermal environment, the OTUS should be designed to satisfy the requirement for planting small trees. If this requirement cannot be adequately satisfied, individuals can also set up tree wells or add soil on top of underground structures to plant small trees, and establish an OTUS that can satisfy the requirement of planting large shrubs in other areas.

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Urban power supply network plays a vital role in maintaining the city operation. The vulnerability of power supply network in the face of events has been one of significant concerns. This study presents a new methodology and framework for “dose-response” vulnerability assessment of urban power supply network. This framework can explore the vulnerability of power supply network under two types of events: random type and intentional type. It also integrates a new metric that calculates the vulnerability of power supply network in both structural dimension and functional dimension. Taking the power supply network of a city in east China as an example, network vulnerability under different types of events was assessed, and the “dose-response” interrelationships between network performance and event scale under different types of events were thoroughly discussed. The results demonstrated that power supply network was more vulnerable to intentional events in both dimensions. For intentional events, power supply network was more vulnerable to degree-based attack than to betweenness-based attack. After that, the redundancy coefficient α of power supply network was optimized. The conclusion and some suggestions for future research were given in the end.