章 俊華

Beijing’s royal gardens represent the highest artistry in the artificial modification and utilization of natural hill and lake landforms. They also encompass the most concentrated ancient Chinese royal architectural heritage complexes. Their sustainable development has drawn significant attention, particularly in detecting and identifying areas of land subsidence and analyzing its influencing factors, which are crucial for preserving Beijing’s royal architectural heritage. This study employed time-series interferometric synthetic aperture radar (InSAR) technology to collect 148 SAR datasets from 2019 to 2023. It compares the persistent scatterer (PS)–InSAR and small baseline subset (SBAS)–InSAR techniques for cross-validation analyses to systematically assess the spatial characteristics of land subsidence of the most valuable architectural heritage complexes in the four most representative Beijing’s royal gardens. The study identified several areas with concentrated subsidence. Further analysis of the types of ancient building locations reveals that buildings situated in hilly areas (Type C), waterside buildings (Type A1), and near-water buildings (Type A2) are more significantly affected by land subsidence. Through an analysis of the causes of subsidence, it was found that, affected by the “excavating lakes and piling hills” landscape modification method and the utilization of natural hilled terrain approach, the subsidence observed in most Type C architectural heritage complexes within the study area may be associated with the Holocene sediments in the underlying soils beneath the shallow foundations of architectural heritage, localized bedrock instability caused by exposure and weathering, and slope instability. Type A building complexes’ subsidence and localized uplift may be associated with Holocene sediments beneath their foundations. The cross-comparison between SBAS-InSAR and PS-InSAR provides a reference framework for exploring land deformation research in architectural heritage sites where detection methods are constrained.

Owing to lifestyle changes since COVID-19, new needs for various usages and spatial experiences of open spaces have become apparent. Suburban parks and green spaces are thought to be suitable uses. This study used structural equation modeling to examine the direct and indirect effects of diverse usages and experiences on the desirability of three proposed park plans for a major park in City A, near Tokyo, based on questionnaire survey data. The findings highlight the importance of “Nature, Passive, and Healing” usage, including nature experiences and small-group activities. “Nature, Passive, and Healing” is negatively affected by “Gathering and Active” but positively by “Multifunctional and Borderless”. A potential for significant improvement in park desirability was also found by linking “Nature, Passive, and Healing” to “Multifunctional and Borderless”. For those aged 60 and older, the indirect effect of “Multifunctional and Borderless” via “Nature, Passive, and Healing” was large and significant, whereas its direct effect was not. “Multifunctional and Borderless” park usage was also been proven to have the greatest impact on female users, whereas, for males, “Nature, Passive, and Healing” had the largest impact. These results emphasize the importance of designs that balance diverse usages and ensure appropriate distancing to meet new needs.