土木工程专业毕业设计外文翻译---地下空间的利用-建筑结构(编辑修改稿)

土木工程专业毕业设计外文翻译---地下空间的利用-建筑结构(编辑修改稿)内容摘要：

c effects of high land prices are of great interest in the study of the potential uses of underground space. When surface space is fully utilized, underground space bees one of the few development zones available. It offers the possibility of the adding needed facilities without further degrading the surface environment. Without high land prices, however, the generally higher cost of constructing facilities underground is a significant deterrent to their environmental, or social groundsluxuries which many developing nation cannot afford at present and which developed nations are reluctant to undertake except in areas of special significance. Planning of Underground Space Effective planning for underground utilization should be an essential precursor to the development of major underground facilities. This planning must consider longterm needs while providing a frame work for reforming urban areas into desirable and effective environments in which to live and work. If underground development is to provide the most valuable longterm benefit possible , then effective zones beneath public rightsofway in older cities around the world. The tangled wed of utilizes monly found is due to a lack of coordination and the historical evolution in utility provision and transit system development. The underground has several characteristics that make good planning especially problematical:  Once underground excavations are made, the ground is permanently altered. Underground structures are not as easily dismantled as surface buildings.  An underground excavation may effectively a large zone of the stability of the excavation.  The underground geologic structure greatly affects the type, size, and costs of facilities that can be constructed, but the knowledge of a region`s can only be inferred from a limited number of site investigation borings and previous records.  Large underground projects may require massive investments with relatively high risks of construction problem, delay, and cost overruns.  Traditional planning techniques have focused on twodimensional representations of regions and urban areas . This is generally adequate for surface and aboveground construction but it is not adequate for the plex threedimensional geology and built structures often found underground . Representation of this threedimensional information in a form that can readily be interpreted for planning and evaluation is very difficult. In Tokyo, for example, the first subway line (Ginza Line) was installed as a shallow line (10 meters deep) immediately beneath the existing layer of surface utilities. As more subway lines have been added, uncluttered zones can only be found at the deeper underground levels. The new Keiyo JR line in Tokyo is 40 meter deep. A new underground super highway from Marunouchi to Shinjuku has been proposed at a 50meter depth. For parison, the deepest installations in London are at approximately a 70meter depth although the main plex of works and sewers is at less than 25 ers. Compounding these issues of increasing demand is the fact newer transportation services (such as the Japanese Shinkansen bullet trains or the French TGV) ofen require larger crosssection tunnels, straighter alignments, and flatter grades. If space is not reserved for this type of use, very inefficient layouts of the beneath urban areas can occur. Environmental Benefits Another major trigger for under ground space usage is the growing international concern over the environment, which has led to attempts to rethink the future of urban and industrial development. The major concerns in balancing economic development versus environmental degradation and world natural resource limitations revolve around several key issues. These are:  The increasing consumption of energy pared to the limited reserves of fossil fuels available to meet future demand.  The effect on the global climate of burning fossil fuels.  The pollution of the environment from the byproducts of industrial development  The safe disposal of hazardous wastes generated by industrial and military activites. Preserving the environment from the byproducts of industrial development economic growth and maintaining individual life styles will be plex if not impossible. However, a high standard of living and high gross domestic product do not have to be proportionately dependent on resource consumption and environmental degradation. Underground space utilization can help solve the environmental/resource dilemma in several ways . Underground facilities are typically energy conserving in their own right. More importantly, by using addition to the obvious benefit of preserving green space and agricultural land, there is strong evidence that higher urban density can lower fuel resource consumption The Future of Underground Space Development Although existing underground facilities throughout the world provide some models for future development, they are all limited in scale, in their lack of a prehensive vision for the total city environment. As a plement to more detailed planning and research studies, it is useful to examine the visions of extensive underground plexes, even entire cities, that have been proposed by futuristic planners and designers. Geotech`90, a conference and exhibition held in Tokyo in April 1990, was a major forum for the underground industry in Japan. More than a dozen underground concepts were displayed, ranging from the typical transit and utility uses to underground corridors that are envisioned as places for a munication work protected during disasters. Such corridors could also effectively transport both waste and energy between substations in the city and central generation and disposal sites outside the city. This approach not only relieves congestion。