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GuangqianWANG BaoshengWU JunqiangXIA 《国际泥沙研究》2004,19(1):75-82
The closure of third stage diversion channel for the Three Gorges Dam is characterized by large closure discharge, large drop in water surface, and high gap velocity. 1D and 2D flow mathematical models were used in this paper to simulate the hydraulic conditions during the closure. The variation of discharge in the diversion channel and the drops in water surface shared by the upstream and downstream cofferdams were computed using the ID model, and the detailed hydraulic patterns in the diversion channel were simulated using the 2D model. The computed results indicate that the designed closure scheme for discharge of 9,010 m^3/s was feasible for construction, while the designed closure scheme for discharge of 12,200 m^3/s was inapplicable. 相似文献
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ON THE VARIETY AND COMPLEXITY OF THE SHORT-TERM AND URGENT PRECURSORS OF THE TANGSHAN EARTHQUAKE 
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下载免费PDF全文 Mei Shirong 《地震工程学报》1985,7(3):72-89
The Tangshan earthquake(M=7.8)which occurred on July 28, 1976 is the greatest event among the modern catastrophes in China. It occurred in a region that was the most densely networked with seismic stations, a region that had the longest history in seismological work and had received 相似文献
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SHEN Huanting Institute of Esturaine Coastal Research East China Normal University Shanghai China LI Jiufa Institute of Esturaine Coastal Research East China Normal University Shanghai China ZHU Huifang Institute of Esturaine Coastal Research East China Normal University Shanghai China HAN Mingbao Institute of Esturaine Coastal Research East China Normal University Shanghai China ZHOU Fugen 《国际泥沙研究》1992,(3)
The Changjiang River is characterized by the enormous volume of runoff and the great amount of sediment load with remarkable seasonal variation. The annual runoff sometimes is respondent to the amount of sediment load, and sometimes not. The amount of monthly sediment load after the month of the maximum runoff is larger than those before the month. The sediment concentration and net quantity of sediment transport in the vicinity of the river mouth varies greatly in time between the ebb and flood, spring and neap, and dry seasons and flood seasons. The three bifurcations also have differences in concentration and net quantity in space. Even in the same bifurcation they have differences in and out of the sand bar. At present, the North Channel is the main passage for water and sediment load emptying into the sea from the Changjiang River. More than 50 percent of the sediments from the river basin are deposited nearby the South Branch entrance and the main depositional area is situated in subaqueous delta off the South Channel. Between 122°30'E and 123°E is an important boundary for eastward sediment dispersion from which the suspended sediment are dispersed towards the east by south. 相似文献
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1 INTRODUCTION Large-scale flood disasters have frequently occurred in the middle Yangtze River since the 1990抯. The Jingjiang River and Dongting Lake (Fig. 1) comprise the most serious area of flood disasters. The main characteristic of recent disasters is low discharge and high water stage. Recent research has begun to pay more attention to the important role of sediment deposition (Li and Ni, 1998). Though the Yangtze River is not an overloaded river, the amount of sediment trans… 相似文献
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Relative sea level change can be derived from tide records. In order to study the general sea level change along the coast of China, it is necessary to make a unified reduction for all the results obtained from various tide stations. A so-called isostatic datum of vertical movement of thecoastal land hasbeen suggested as a basis of the unified reduction in this paper, established by useof precise releveling data completed between 50's and 80's.The vertical movement velocities relative 相似文献
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Cailan GONG Caixing YUN Jianjun JIN Ph.D. State Key Laboratory of Estuarine Coastal Research East China Normal University Shanghai China Professor State Key Labora 《国际泥沙研究》2002,17(1)
1 INTRODUCTION The Changjiang River (Yangtze River) is bifurcated into North and South Branches by the Chongming Island (Fig. 1). The North branch is further divided into the North channel and South channel by the Changxing and Hengsha Islands, and the… 相似文献
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ＴＨＥＲＩＶＥＲＣＨＡＮＮＥＬＡＤＪＵＳＴＭＥＮＴＡＳＩＮＦＬＵＥＮＣＥＤＢＹＴＨＥＦＬＯＯＤＰＬＡＩＮＧＥＯＥＣＯＳＹＳＴＥＭ：ＡＮＥＸＡＭＰＬＥＦＲＯＭＴＨＥＨＯＮＧＳＨＡＮＲＥＳＥＲＶＯＩＲ￥ＸＵＪｉｏｎｇｘｉｎ；ＳＨＩＣｈａｎｇｘｉｎｇ（Ｐｒ... 相似文献
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ABSTRACT An infiltration model based on the Green-Ampt assumptions is developed for a class of non-uniform soils in which saturated hydraulic conductivity decreases as an exponential function of depth, and the storage-suction factor C = ΔθΔΨ is a constant. An analysis of measured hydraulic conductivity and porosity data suggests that the model may be useful in some soils where the changes of hydraulic characteristics with depth are of this form. A method for using the model with time variable rainfall rates is given. The model is applied to simulate the experimental results of Childs &; Bybordi (1969) who measured infiltration into layered sand profiles. Agreement was satisfactory even for this case. 相似文献
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U.C.E. ZANKE 《国际泥沙研究》2003,18(1)
1 PROBLEM DEFINITION Owing to the practical importance of the initiation of motion many researchers began to tackle this problem even at the beginning of the last century (e.g. Kramer (1932, 1935), Casey (1935)). Shields (1936, Fig. 1) developed a non-dimensional representation based on the measured data of Casey, Kramer, USWES and Gilbert, together with his own data based on investigations with succinite sand, lignite, granite chips and heavy spar. Despite the different material p… 相似文献
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~~THE EFFECTS OF TURBULENT BURSTING ON THE SEDIMENT MOVEMENT IN SUSPENSION@Ye MAO$Hohai University!Nanjing 210098 China~~ 相似文献
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TU Qiming Engineer Navigation Office of the Three Gorges Project Ministry of Communication 《国际泥沙研究》1991,(3)
Sedimentation problems in the access channels of the Gezhouba Navigation Locks at the Third Channel, which is of great importance for the navigation are discussed in this paper:1) the cause of deposition in the access channel, 2) effects of the deposit--reducing embankment and sediment sluices and 3) the relation between the sediment deposition at the Third Channel and the sediment discharge of the Yangtze River. Analyzing a four years' field data of sounding records with respect to the lock operation, it can be seen that the flood release through the navigation channel resulted in severe deposition, especially the sediment deposits induced by eddy current are difficult to be cleared off by flushing and jeopardize the working conditions of the lock operation. It is obvious that the flood release through the navigation channel should be minimized. In order to reduce the sediment deposits caused by eddy current attempts should be made to adjust the alignment of the boundaries and layout of the entrance of access channels. 相似文献
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LEI Kun YANG Zuosheng GUO Zhigang Doctoral student College of marine geosciences Ocean University of Qingdao Qingdao China Assistant prof. the Chinese Research Acad 《国际泥沙研究》2002,17(2)
1 INTRODUCTION The East China Sea, one of the largest continental marginal seas in the world, receives large amount of suspended sediment from the land annually (Milliman and Meade, 1983; Shen, 1999). Since late Pleistocene, the deposition of the suspended sediment over the relict sandy sediment induces the complicated distribution of surface sediment (Fig. 1). Many studies have been done on the surface sediment distribution, sedimentation rate, concentration and dispersion of suspen… 相似文献
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Based on the data of 18 times of leveling carried out during 1954 to 1985, the relative stability degrees of relevelling nodes in the Tangshan area are calculated. According to these results, the characteristics of crustal vertical deformation before and after the Tangshan Earthquake(28/7/1976,Ms =7.8) are studied. Our study indicates that probably since 1968 significant relative movements between structural blocks in that area had appeared and continued till 1978. The seismic fault wa 相似文献