The determination of the hydraulic fill elevation is one of the urgent problems in reclamation project. The determination of the hydraulic fill elevation is of extreme importance to the final design elevation in reclamation project. If the hydraulic fill elevation is over high, might waste the hydraulic fill resources, and soil strength would decreased greatly when reduce the topsoil to reach design elevation. If the hydraulic fill elevation is over low, twice-fill is needed leading to great increased coast. In the paper, observational settlement prediction system of dredger fill had been established by research of BP artificial neural network. Finally, the hydraulic fill elevation of reclamation project was suggested reasonably by the observational settlement prediction system.
Reservoir regulation and reservoir sedimentation make conditions of flow and sediment under the dam change greatly after impoundment of the Three Gorges Project. This paper analyzes change trend and abrupt change situation of incoming water and sediment and studies characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method. The result indicates that operation of the Three Gorges Reservoir has leveled runoff process and shortened dry season and extended median water period. After operation of the Three Gorges Reservoir, annual sediment runoff and monthly sediment runoff of some months changed suddenly and sediment runoff reduced sharply in Yichang Station. Sediment entering the middle and the lower reaches of the Yangtze River decreases substantially and it almost can be regarded as clean water discharge. Intorduction After operation of 175m normal water level of the Three Gorges Reservoir, total storage capacity of the reservoir is about 43 billion m3. Most of incoming sediment in the upstream is intercepted and deposited inside the reservoir and clean water and muddy water containing non-bed sand discharges. Change of water and sediment conditions destroys balance of downstream river and causes bed-rebuilding of downstream channels. And this results in a serious of long-term and long distance changes, such as on-way recovery of sand content, undercutting of bed scour, expansion of bank erosion and decline of water table, etc.[1-. Yichang Station controls a drainage area of 1005501km2 in upstream of the Yangtze River and is a major flood source for the middle and the lower reach of the Yangtze River. Thus, water regime information of Yichang Station is significant to flood control of the middle and the lower reach of the Yangtze River, regulation of the Three Gorges Reservoir, construction of water conservancy project all across the Yangtze River, industrial and agricultural production and shipping, etc. On account of this, this article analyzes data about coming water and sediment of Yichang Station to support characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method.
Dongbei waterway in the lower reach of Yangtze River includes three waterway: Hukou waterway, Heng waterway and Zhi waterway. The evolvement trend based on the measured data show that the right branch of Xiasanhaozhou is developed and the shallow shoal at the head of Xiasanhaozhou is scoured along with the right branch be rushed and ratio of diversion flow increase which have negative effect on transition shoals. In order to analysis the effect of evolvement trend on the channel conditions of transition shoals, this paper adopt cognitive calculation on water flow of Dongbei waterway using mathematic model. The results show that, the development of right branch of Xiasanhaozhou and the shallow shoal cutting at the head of Xiasanhaozhou decrease velocity of transition sections, decrease the diversion flow of the left branch of Xiasanhaozhou, and increase the diversion flow of the head of Xiasanhaozhou which have negative effect on transition shoals.
The waterway of Jiangxinzhou to Wujiang section is the only hindering navigation section in Wuhu to Nanjing of the lower reaches of the Yangtze River. Because of the unsteadiness of the main stream, the navigation condition in this section tends to worse, in which the regulation work is sorely needed and more important. The major problem for channel regulation in this section is the design of regulation project. In this paper, the 2D numerical model for simulating the flow and sediment in the waterway of Jiangxinzhou-Wujiang section is used to analyze these questions. From the numerical simulation results, we know that the overall navigation regulation project can solve the problem of hindering navigation.
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