Coupling Relationship Between Summer Microclimate and Spatial Layout of Street Canyons in the White Stupa Temple Area of Beijing

With the rapid urbanization, many high-rise buildings and new districts have been built continuously. However, the old town of cities has gradually been forgotten by people and its environment is becoming increasingly harsh. The old town usually has diversified space and function. As an important part of the old town, the street canyon that is closely related to human settlements is a public space where people communicate and do activities. Therefore, research on microclimate-based improvement of the street canyon in the old town is of great significance. Six typical street canyons in the White Stupa Temple area of Beijing were selected for research to explore spatial characteristics of the street canyon. Microclimate factors such as temperature, humidity, wind speed, and solar radiation were measured on the spot in summer. These factors were combined with two microclimate assessment indexes of physiological equivalent temperature(PET) and wet bulb globe temperature(WBGT) to evaluate the microclimate of the street canyon. In the analysis of the measured data, the mean value comparison method was used to analyze the average values of the microclimate factors in different time periods. Spatial layout of microclimate included the orientation of the canyon, the ratio of the canyon height to canyon width, and green coverage of the canyon, and an in-depth study was made on the coupling relationship between the spatial layout and the microclimate of the canyon. Research results can provide an optimization strategy for the transformation design of the street canyon in White Stupa Temple area, and provide a scientific reference for the research on spatial layout and microclimate improvement in the old town, so as to improve the living quality of residents in the old town.

Numerical analysis of stability for mined-out area in multi-field coupling

There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.