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161.
长江口深水航道治理工程综述 总被引:3,自引:0,他引:3
文章概要地介绍长江口深水航道治理工程的规划、勘察、设计和施工情况,对整治方案及主要岩土工程问题略作讨论。 相似文献
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Andreas MALCHEREK Research Engineer Federal Waterways Engineering Research Institute 《国际泥沙研究》2001,16(2)
1 INTRODUCTIONThe numerical simulation of morphological changes in rivers, estuaries and coastal areas is because ofits econondcal merit an outstanding scientific task. The comPlexity of the problem is connected with theheterogeneity of the sediment material, an adequate rePresentation of the involved hydrOdynndc stressesand the large comPutational effort fOr long term simulations.Although the aPpllcation of three dimensional models tO engineering problems is increasing and wellvalldate… 相似文献
164.
Protection of groundwater already is and will also be in the future, a particularly important environmental, socio-economic, social welfare and political task. The fact that the costs of preventive measures are 10–20 times lower than the funds needed to clean up and revitalize polluted aquifers, as well as the fact that the area to be occupied with transport communications and other infrastructure facilities will aggravate protection, both call for an urgent introduction of modern methods of monitoring and preserving all the existing and potential groundwater resources. The basic principle of groundwater protection against pollution means constant control and preventive measures of protection, namely prevention of incidental and other kinds of pollution. The very construction of communications and all accompanying facilities changes and degrades the existent natural geological environment, and when in use they may become structures in whose immediate surrounds surface and ground waters may be polluted by the toxic and waste substances transported. The experience gained through the following activities: the ‘pilot model’ for groundwater monitoring in the zone of Makis, the investigations and monitoring of critical sites polluted with xylene (CIP, Belgrade, 1994/95), and information on the latest achievements in this field in the world (obtained while working on the study of methodology of hydrogeological investigations needed for groundwater quality monitoring system — Jaroslav Cerni Institute for the Development of Water Resources, Belgrade, 1998), stresses a necessity to obligatory design and construct operational systems for groundwater quality monitoring, particularly in the zones of infrastructure facilities (roads, railway, gas pipelines, oil pipelines), which can be considered as potential linear polluters. In that light, this paper is a contribution to developing hydrogeological investigation methodology for designing and operating a monitoring system in the zones of roads, and its legal and practical incorporation in the technical documents of each project. Besides, an emphasis is put on multidisciplinary approach to system implementation, its full automation, rational management, and effective and optimal measures for groundwater protection. 相似文献
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广州市土地资源的保护和可持续利用研究 总被引:7,自引:1,他引:7
本文分析了广州市土地利用的结构及其变化趋势,指出土地利用上存在的主要问题和隐患 为采取有效措施,加强对耕地和环境的保护,以保证土地资源的可持续利用。 相似文献
167.
I.EnvironmeotaICharacterishcsofChangliCountyChangliCoLmtyislocatedinthenortheastermendoftheNorthChinaPlain,nexttoBohaiSeaontheeastandthesouthemendofYanshanMountainsontl1enortl1.Luani1emverWhichrunsthroughthecouotyforn1sthewestemandsouthemboundaryoftitiscoastalcounty.ThenorthempartofthecoUnyishillywithaverageheigltrrangingfrom5oto5Oom,andmostportionintheeastemandsouflempartislocatedonthealluvialplainofLuani1eandYirunarivers,inclilungfromnorthwesttosoutieastwiil1heighrangingfrom2to3m.Tl1… 相似文献
168.
In this paper the researches made in 1981-1990 have identified that the annual soil loss in the Three Gorges region is 157 million t. and the annual incoming sediment load of the Three Gorges reservoir is 40 million t. Soil erosion increases with the destruction of vegetative cover and its subsequent evolution. The annual amounts of sediment erosion for forest land, shrub land, grassland and farmland make up respectively 6.19%, 10.76%, 23.05% and 60% of the total erosion of the Three Gorges region; the quantities of incoming sediment load to the Yangtze River from the above four types of land account for 5.95%, 12.42%, 35.46% and 46.1 % of the total amount of sediment transported to the reservoir. The farmland of offers the main source of sediment. Gravitational erosion produces more bed loads, which will present serious threat to the Three Gorges Project if entering the reservoir. Resettlement of people to the upper parts of the mountainous areas for agricultural production will increase the sediment yield of the Three Gorges region by 10-20 million t and increase the incoming sediment of the Yangtze River by 50-60 million t. Consequently, it is necessary to make a realistic assessment of the soil erosion in the Three Gorges region. 相似文献
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170.
Roger A. Kuhnle 《地球表面变化过程与地形》1992,17(2):191-197
Bed load transport rates were measured with continuously recording pit samplers on two small gravel-bed streams in the Goodwin Creek Research Watershed, northern Mississippi, U.S.A. When transport samples were grouped according to whether the stage was rising or falling, significant differences in mean bed load transport rates were found at nearly all flow strengths. At higher flow strengths, mean bed load transport rates were greater during rising stages than during falling stages. The greater transport rates measured during rising stages may be caused by a lag in the formation and destruction of bed roughness elements. One of the streams also showed evidence for greater transport rates for low flows as the stage declined. This may be caused by differences in the stability of the bed material at the beginning and at the end of a transport event. 相似文献