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Hugen ZhU Associate Prof Dept. Of Civil Eng. Hefei University of Technology Hefei China Zhaoyin WANG Prof Dr. International Research Training Center on Erosion Sedimentation P.O. Box Beijing China Dieter PRINZ Prof. 《国际泥沙研究》1997,(3)
LIN~DUCnONTheHuaiheBasinislOCatedbetWeen31"-36"llorthemlahtudeand112"-121"easternlongitude,andcoversatotalareaofabout269,000sq.kin,OfwhichthemountainousandhillyareasocCUPyl/3,theplainsandlow-iringland2/3.ThebasinelicitSsalientphysicalgeographicalfeatllTesasfollowsf(l)Thereisnoobviousmountaindividebe~ntheWatershedoftheriVerandtheYellowforerBasinaswellastheYangtZeRadBasin.MostofthetributariesinthenoalbudoftheHuaiheforertakethesouthdikesOftheYellowherasthedivide.(2)TheriVerbedofthetr… 相似文献
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河北阳原东目连第四纪叠层石古环境分析 总被引：7，自引：3，他引：7
组成阳原县东目连湖积台地的第四纪“泥河湾层”地层中,发育多层藻迹层和一层“菜花形”、“锥体状”大叠层石(个体高20 cm),大叠层石层延伸1 km,构成古藻坪微地貌。经OSL和古地磁测试,大叠层石年龄推测为220 ka左右。镜下叠层石片子中见蓝藻门的纤细席藻种Phormidium tenue(Menegh)Genegh和湖泊鞘丝藻种Lyngbya Limnetica Lemmermann等。不同形态叠层石反映不同发育阶段,藻迹发育于高水位边缘部位,大叠层石发育于高水位与低水位之间边缘部位。亮层和暗层交替出现的纹层构造是组成叠层石的基本结构构造,它们是由蓝藻丝体生长代谢活动所致。据同位素、磁化率、粒度、地球化学元素、X衍射、孢粉和生物化石等分析,认为气候暖干、盐度高及大量苔藓虫、介形虫、龙介科蠕虫等生物存在的环境有利于大叠层石形成。叠层石可能属半咸水湖、滨湖浅水环境,但据首次在第四纪泥河湾层中发现的苔藓虫和龙介科蠕虫管分析,其成因是否与海水有过联系尚待进一步研究。 相似文献
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ZHOU Prof Dr. -Ing. Sedimentation Division Department of Hydraulic Engineering Tsinghua University Beijing J. China. SPORK Research Engineer Dip.-Ing. Institute of Hydraulic Engineering Water Resources Developmot Aachen V. University 《国际泥沙研究》1997,(3)
I.INTRODUCTIONSuspendedsedimenttransportissaidbeinanycaseaphenomenaofa3Dprocess.Becauseofthelimitationsincomputercapacity,mostoftheexistingmodelstreateditasatlvoorevenonedimensionalproblem.WiththerapidadvancesofcomputersinbothCPUandmemorycapacity,andbecauseoftheavailabilityof3Dmodelsforturbulentflowsimulationsinpracticalapplications,thefully3Dsimulationofsuspendedsedimentbecomesafeasibleandurgenttaskforhydraulicengineers.TheprocessofsuspendedsedimenttransportisdescribedbytheadVection-d… 相似文献
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Strategies for managing reservoir sedimentation 总被引：2，自引：1，他引：1
Zhao-yin WANG Chunhong HU Prof. State Key Lab of Hydroscience Engineering Tsinghua University Beijing China. Prof. Secretary General of International Research Training Center on Erosion Sedimentation Beijing China Vice President of China Institute of Water Resources Hydropower Research No. A- Fuxing Rd Beijing China. 《国际泥沙研究》2009,24(4):369-384
Sediment deposition in reservoirs has caused the loss of 66% of the reservoir capacity in China. The main sedimentation control strategies are： 1） storing the clear water and releasing the turbid water; 2） releasing turbidity currents; 3） Draw-down flushing and empty flushing; and 4） dredging, The paper summarizes these strategies with examples. Sediment transport in many Chinese rivers occurs mostly during the 2-4 month flood season, that is, 80-90% of the annual sediment load is transported with 50-60% of the annual runoff. By storing the clear water after the flood season and releasing the turbid water during the flood season, less sediment deposits in the reservoir while the reservoir is still able to store enough water for power generation in the low flow season. The Three Gorges and Sanmenxia reservoirs apply this strategy and control sedimentation effectively. Turbidity currents have become the main sedimentation control strategy for the Xiaolangdi Reservoir. Empty flushing involves reservoir draw-down to temporarily establish riverine flow along the impound reach, flushing the eroded sediment through the outlets. Case studies with the Hengshan Reservoir and Zhuwo Reservoir are presented. Jet dredgers have been used to agitate the reservoir deposit so that the deposit is released from the reservoir with currents. The sediment releasing efficiency is 30-100% for storing the clear and releasing the turbid; 6-40 % for turbidity current; and 2,400-5,500% for empty flushing. Empty flushing causes high ecological stress on the ecosystem to the downstream reaches. Storing the clear and releasing the turbid is the best strategy to control reservoir sedimentation while achieving hydro-power benefit and maintain ecological stability. 相似文献
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Zhaoyin WANGProf Dr. International Research Training Center on Erosion Sedimentation. P.O.Box Beijing China Jinchi HUANG Dr. Senior Engineer China Institute of Water Resources Hydro-Power Research P.O.Box Beijing . Chi 《国际泥沙研究》1997,(3)
I.INTRODUCTIONhiverchannelsaresubjecttocontinuouschangeingeometryduetoillteraCtionbetWeentheflowanderodibleboundaries.Ofconcerntothedesignersofoilpipelinesacrossariver,bridgesandhydraulicworksistheproblemofscourwhichcanunderminetheStructures.Scouratsiteofbridgesandhydraulicworksoccursduetoconstrictedflowandexistenceofbridgepiers.SuchatabOfscouroccursonlyinashortsection,usuallyillthesameorderofthelengthofthehydraulicworksorbridges.Therefore,thispatternofscouriscalledlocalscour.Man}rresea… 相似文献
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The Haihe cohesive sediment, which is typical in China, is studied systematically for its basic physical and incipient motion properties. Following the requirements of dredging works in the Haihe Estuary, cohesive sediment samples were taken from three locations. Laboratory experiments were conducted to delermine the rheological properties of these samples and to examine the incipient motion of the cohesive sediment. it is found that the cohesive sediment has an obvious yield stress τb, which increases with the mud density in a manner of an exponential function, and so does the viscosity parameter η. The cohesive sediment behaves like a Bingham fluid when its density is below 1. 38 - 1 .40 g/cm3 , and when denser than these values, it may become a power-law fluid. The incipient motion experiment also revealed that the incipient velocity of the cohesive sediment increases with the density in an exponential manner. Therefore, the incipient motion is primarily related to the density, which is different f 相似文献
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对巢湖北部地区以碳酸盐岩为主的寒武系—下三叠统海相地层的黏土矿物分析及伊利石结晶度测定的结果表明:伊利石是本区海相地层的主体矿物,平均体积分数为73%。黏土矿物的成岩转化特征表现为蒙皂石的伊利石化。按照伊利石结晶度的成岩-浅变质程度划分,本区寒武系—下三叠统的成岩作用已达到最高成岩阶段。伊利石结晶度的纵向变化总体上可分为上、下两部分:下部寒武系至志留系的结晶度为0.41～0.60°Δ2θ,结晶度与埋深具有一定的相关性,成岩作用是下部地层黏土矿物特征的主控因素;上部泥盆系至下三叠统的结晶度为0.45～0.77°Δ2θ,呈波动变化,蒙皂石连续出现,地层没有被显著埋藏,沉积因素是上部地层黏土矿物特征的主控因素。下三叠统地层中蒙皂石的分布特征以及上泥盆统五通组顶部高岭石的普遍富集具有重要的古气候研究意义。 相似文献
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1 INTRODUCTION Bohai Bay suffers from eutrophication and red tide has been occurring frequently since the 1990s. The water pollution is caused by pollutants originating inland that account for 87% of all pollutants entering the bay. More than 40 rivers flow into the bay carrying 95% of the total pollutants and nutrients from inland sources (Zhao and Kong, 2000). Among these rivers, the Yellow, Liaohe, Luanhe, Haihe and Jiyun Rivers are the largest, which carry 1.3 109 t of sediment lo… 相似文献
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