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疏浚土倾倒后悬浮泥沙扩散输移的数值模拟 总被引:1,自引:0,他引:1
疏浚土的处置是航道疏浚整治中需要解决的问题.疏浚土在倾倒区倾倒之后,大部分疏浚土会沉积在抛泥区附近,其余泥沙将在抛泥点的局部区域形成高浓度悬沙,在重力、波浪、潮流、风生流等因素作用下扩散输移.建立了平面二维潮流、悬沙浓度增量输移扩散的数学模型,采用有限单元法离散求解,研究了虾峙门口外航道整治工程中疏浚土倾倒后悬浮泥沙在水体中的扩散输移,以此分析抛泥后不同悬沙浓度增量的悬浮泥沙的扩散范围.虾峙门口外外海处设置了1#、2#、3#倾倒区,模型计算结果表明,各悬沙浓度增量的悬浮泥沙扩散最大面积的最小值及包络线面积的最小值均发生在3#倾倒区抛泥的工况,原因在于3#倾倒区位于外海,水深明显大于1#、2#倾倒区,其倾倒区容积最大.可见,在水动力条件相当的情况下,水深条件形成的各倾倒区容积对悬浮泥沙的扩散和输移是有影响的.倾倒区容积越大,对悬浮泥沙扩散和输移越有利.从经济因素来看,疏浚船的运输距离所发生的运费是不可忽略的,疏浚航道至1#、2#倾倒区的距离要短于至3#倾倒区的距离,把疏浚土运至1#和2#倾倒区的运行费用明显低于运至3#倾倒区的运行费.研究结果建议,选择1#和2#倾倒区为疏浚土倾倒区,并根据潮流方向灵活安排施工作业,可将1#倾倒区作为落潮时疏浚土的倾倒区,2#倾倒区作为涨潮时疏浚土的倾倒区. 相似文献
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随着我国沿海地区社会经济的飞速发展,港航工程建设及维护产生的疏浚泥产量急剧增加,规模化、产业化实现疏浚泥资源化处理综合利用刻不容缓。文章以海洋固体废弃物资源化再利用为宗旨,结合南海规划与环境研究院近20年来在该领域的理论研究基础与工程实践经验,系统分析了海洋疏浚泥资源化利用技术成果推广转化面临的“瓶颈”,从建立永久性基地困难、产业链整合程度较低、成本造价竞争力不强、设计施工过程较保守、复合型管理人才缺乏等方面进行了思考分析,并有针对性地从加强基础研究应用、建立协同创新机制、建立交流合作网络、强化知识产权保护、健全政策法规体系、完善行业管理机制等角度为相关管理决策部门提出了具有可操作性的对策与建议。 相似文献
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连云港疏浚工程的环境效应—以羊窝头抛泥区为例 总被引:7,自引:0,他引:7
以连云港羊窝头抛泥区为研究区域,对疏浚工程中产生的大量疏浚弃土倾倒入海后,所产生弃土的堆积-流失=扩散过程以及海域环境效应,进行了现场观测和计算,并从物理、化学和生物3个方面对海区的水质、底质和生态环境的影响作出客观分析,认为疏浚的环境效应主要三长两短拭个方面对海区的水质、底质和生态环境的影响作出客观分析,认为疏浚的环境效应主要取决于疏浚弃土本身的受污染程度,而对海域环境的影响,则主要是弃土扩散所造成的海水中悬浮沙量增加引起水质浑浊度的增高的物理性影响,同时由于弃土中大量的粘粒和胶粒物质具有吸附海水中重金属和采购物等污染物质的能力,有利于水质和生态环境的改善,因百对各类海洋生物生态环境的影响是十分轻微的。 相似文献
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为了分析海洋水体垂向水流紊动及紊动交换情况而采用了一维的海洋边界层模型(Mellor-Yamada)并利用数值实验的方法对悬沙、盐度、温度等数据进行分析。原模型未将悬沙考虑在内,本文试将它引入进去探讨由于它的存在对紊动混合特性的影响。2000年4月,Mellor将最初的模型引入了依赖于Richardson数的紊动动能耗散率。本文通过比较具有悬沙和不具有悬沙两种情况下的速度、温度和盐度垂向分布随时间的变化,分析讨论由于悬沙的存在所引发的密度层化对紊动混合作用的影响,并发现悬浮泥沙抑制了部分模拟时间的紊动混合作用。 相似文献
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葡萄牙特洛亚半岛海滩近十余年受到强烈侵蚀,海浪冲刷到数千万年稳定的古罗马遗址,在2006—2007年,当局将28.6万m3港口航道疏浚沙抛填至海滩上,进行养滩修复,效果较好,扩宽了干滩,稳定了古罗马遗址,发展了旅游业。这不仅是一个完美高效的养滩工程,而且还是一个极其节约的工程,使用疏浚沙不仅降低了运输费,还为港口节约了购买抛沙海域的费用。我国港口航道甚多,每年至少约有8亿m3疏浚沙,很少用于养滩工程,反而购置河道沙和邻近河口沙。若改用疏浚沙养滩,可极大地降低养护成本,既可节约购沙经费,还可为港口部门节约抛沙海域的购置费用,而且也能为抛沙取沙海域维持正常的航运环境。 相似文献
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海洋功能区划问题及对策探讨 总被引:1,自引:0,他引:1
随着海域使用管理工作的不断深入,作为合理利用海域资源的保障,海洋功能区划将面临着新要求和新任务.因此,以满足海域使用管理新需求为导向,海洋功能区划应立足于体系不断完善.本文着眼于解决区划体系发展的实际需求,探讨了海洋功能区划政策导向,分析了海洋功能区划体系存在的主要问题,并提出了解决问题的对策,为海洋功能区划体系完善提... 相似文献
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航道疏浚是海岸带人类活动的重要形式之一,对近岸海洋环境有着重要的影响。本研究以葫芦岛航道疏浚为例,通过X射线衍射物相分析、放射性同位素分析和激光粒度分析等方法,对航道疏浚区及邻近海域沉积物进行了系统的研究,结果表明:(1)航道疏浚产生的沉积物与现在海底沉积物在粒度组成、黏土矿物组合和210 Pb、137 Cs放射性强度等方面具有显著的差异,可以作为示踪航道疏浚物质扩散和影响范围的指标;(2)葫芦岛海域的航道疏浚物在潮流的作用下沿西北和西南2个方向扩散,不同程度地加入到表层沉积物中,个别地方疏浚沉积物直接覆盖到原沉积物之上,导致海底原地沉积物属性的改变。 相似文献
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概述了海洋环境对桥梁下部结构(包括基础、承台、桥墩等)的影响,并介绍了跨海大桥在下部结构设计、施工中采取的相应措施,以期为跨海大桥下部结构的设计提供参考。 相似文献
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海洋环境中重金属在贝类体内的蓄积分析 总被引:11,自引:0,他引:11
根据2006年5—7月贝类体内重金属含量和海洋环境背景值的调查资料分别分析了海州湾、吕泗、嵊泗和舟山海产贝类重金属与环境中重金属含量之间的关系。结果表明:影响贝类体内重金属Hg,Cd和Pb含量的主要因素是水体中的重金属含量而不是沉积物中的重金属含量;重金属在贝类体内的富集程度由高至低依次为Cd>Hg>Pb;不同贝类对重金属富集效果比较,紫贻贝(Mytiluse dulis)对重金属富集效果最为明显,红螺(Rapana bezoar)对重金属富集效果较其它物种较轻。 相似文献
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Marine pollution has received considerable attention during the past few years as the news media has focused on such topics as contaminated seafoods, algae blooms, fish and mammal kills, and dirty beaches. The source of these pollution problems are many and include: sewage outfalls, industrial discharges, storm runoff from agricultural lands and metropolitan areas, waste sludges, dredge materials, and highly concentrated chemical and radioactive wastes. Although the United Nations has banned marine dumping, there is still the problem of legacy wastes and low level discharges into the coastal zone. Disposal of these wastes in the marine environment typically involves either: their placement directly on or within the seabed or dilution in the water column. If wastes are diluted in the water column, they have the potential to be adsorbed onto the surface of sediment particles which are settling to the seabed. As particles settle through the water column they are subjected to extensive dispersal and may eventually be injested by bottom-feeding organisms or bio-accumulation by plankton and, thus, enter the food chain. Geotechnical engineers working as members of multidisciplinary teams apply quantitative knowledge about the behavior and physical performance of earth materials toward designing systems for disposing of these wastes in the oceans and aid in monitoring waste disposal sites. In dredged material disposal geotechnical engineers assist in selecting disposal equipment, predict stable characteristics of dredged material mounds, design mound caps, and predict erodibility of the material. With sewage outfalls, geotechnical engineers design foundation and anchor elements, estimate scour potential around the outfalls, and determine the stability of deposits made up of discharged materials. Geotechnical engineers also consider the influence that pollutants have on the engineering behavior of marine sediment and the extent to which changes in behavior affect the performance of structures founded on the sediment. In each of these roles, careful application of geotechnical engineering principles can contribute toward more efficient and environmentally safe disposal operations. 相似文献
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Kenneth R. Demars 《Marine Georesources & Geotechnology》2013,31(3):219-235
Marine pollution has received considerable attention during the past few years as the news media has focused on such topics as contaminated seafoods, algae blooms, fish and mammal kills, and dirty beaches. The source of these pollution problems are many and include: sewage outfalls, industrial discharges, storm runoff from agricultural lands and metropolitan areas, waste sludges, dredge materials, and highly concentrated chemical and radioactive wastes. Although the United Nations has banned marine dumping, there is still the problem of legacy wastes and low level discharges into the coastal zone. Disposal of these wastes in the marine environment typically involves either: their placement directly on or within the seabed or dilution in the water column. If wastes are diluted in the water column, they have the potential to be adsorbed onto the surface of sediment particles which are settling to the seabed. As particles settle through the water column they are subjected to extensive dispersal and may eventually be injested by bottom-feeding organisms or bio-accumulation by plankton and, thus, enter the food chain. Geotechnical engineers working as members of multidisciplinary teams apply quantitative knowledge about the behavior and physical performance of earth materials toward designing systems for disposing of these wastes in the oceans and aid in monitoring waste disposal sites. In dredged material disposal geotechnical engineers assist in selecting disposal equipment, predict stable characteristics of dredged material mounds, design mound caps, and predict erodibility of the material. With sewage outfalls, geotechnical engineers design foundation and anchor elements, estimate scour potential around the outfalls, and determine the stability of deposits made up of discharged materials. Geotechnical engineers also consider the influence that pollutants have on the engineering behavior of marine sediment and the extent to which changes in behavior affect the performance of structures founded on the sediment. In each of these roles, careful application of geotechnical engineering principles can contribute toward more efficient and environmentally safe disposal operations. 相似文献
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