The Strategy Research On Urban Underground Space In High-density Area

The development of underground space in a large scale is inevitable when urbanconstruction and economic development have reached certain level. Yet the trickypart is how to blend the underground space into the urban spatial system so as toimprove city quality in China. Nowadays, the construction of underground spacecannot catch up with the fast increase of building density. This will lead to manyproblems: shortage of urban floor space, aggravation of traffic jam, insufficientlandscape planting, serious environmental pollution, and lack of humanized space, etc.Our ability of economic construction has improved substantially, and under such abackground, comprehensive development and utilization of underground space ispossible. And a scientific and reasonable usage of underground space will relieve thepressure of land scarcity and improve the environment quality. This thesis is devotedto the exploitation and utilization of underground space, optimization of urbanenvironment in high-density development area, and the construction of a compact,three-dimensional and efficient urban space system.In European countries, the development of underground space started with theconstruction of subways. However, in China, our underground space was originallyutilized for air defense project in both peacetime and wartime. Therefore, from thevery beginning, we failed to incorporate the underground space into the overalldevelopment of urban space. The trend today is to balance the development andutilization of space overground as well as underground. The exploitation ofunderground space, which includes the construction of city subway and undergroundbuildings, has the potential to meet the increased spatial need. For a sustainable urbandevelopment, the integrative growth of overground and underground space is asignificant task for the optimization of urban spatial system.With the advancement of urbanization, problems of population high density,architecture high density and economic high density mix together and pose greatspatial needs for certain areas. In addition, urban and rural structure in China isundergoing changes. After30years of rapid urbanization, our focus has shifted fromurban quantity to urban quality. So in those cities, where the density of population and architecture is high, we should explore the methods, rules and modes of combiningunderground architecture space, underground transport space and undergroundenvironmental safety space together. Only in this way can we realize the compact,efficient, healthy, and all-around urban development.This thesis focuses on the development characteristics and development modes ofunderground space in high-density urban areas. Space exploitation attributes, spacetypes, density numeric features will be studied in this thesis; the necessity of spatialagglomeration will also be analyzed. Urban center, core region of old city and areassurrounding the rails (TOD mode) are in urgent need of systematic spatial expansion.And the realization of such expansion is highly possible in these regions. Guiding theintegrated spatial exploitation in these places is beneficial for the mixed landdevelopment and the three-dimensional transport development.Firstly, the thesis analyzes the huge demand and the complexity of undergroundspace in high-density cities. Through theoretical problem research, typical casedemonstration and practical experience summary, Beijing Wangfujing commercialdistrict (a commercial district of high density) will be investigated. And problems ofspatial demand and contradictions in this region will be thoroughly surveyed. Thisthesis expounds the complexity and dilemma of land usage in high-density areas andargues the importance of underground exploitation for supporting the overgrounddevelopment.Secondly, this thesis chooses four typical regions as study focus–urban CBD,new town center, core region of old city, and areas surrounding rail station. Theunderground space exploitation type, intensity, scale, and its relation with overgrounddevelopment density will be studied. This thesis will also study the methods andpractices of underground utilization; specific research problem include: the extensionof urban function through underground space, building space organization, organizingmeasures of subway transport and underground parking. On the bases of case studiesand planning proposal, this thesis will put forward the innovative design andtechniques of the integration of underground space and the overground space.Thirdly, a higher environment and safety standard is required for undergroundspace. Therefore, this thesis will study the geological environment and theenvironmental quality standards of the underground to be exploited. Bothmacroscopic and microscopic problems will be considered. Based on the requirement of high quality and high security, the underground space should value theimprovement of environmental condition, the amelioration of underground dampnessand heat, ventilation, and sterilization. Through the ecological, artistic as well as safedesign of the underground space, the underground space will be more compatible withthe overall built environment.At last, the thesis summarizes and perfects the planning formulation system andthe design procedures of underground space. In terms of the methods of spatialconstruction, the thesis puts forward five principles: flexible mapping, compactpolymerization, network island chain, shortcut track, and sustainable order. It alsoproposes three typical modes: ring connection, ridge axis drive, dendritic growth.Other points discussed in this thesis include: the level, content, and techniques ofunderground space planning design; the methods of integrated design of undergroundspace and overground space.