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1.
三峡工程对长江口岸滩的影响   总被引:3,自引:0,他引:3  
三峡工程的兴建将改变河流的来水来沙条件,必然地人坝址下游至长江口地区带来一系列影响,根据多次长江口水下地形资料,分析研究了长江口内外岸滩各自的演变进规律,得出口内岸滩的坍失并非上游来沙量的减少,而是河床淤积、主槽摆动所致;通过点绘上游来沙量与口外南汇边滩的冲淤变化关系图,发现两者存在良好的线性关系,同时综合分析了三峡工程坝址以下河床情况,对三峡工程兴建后大通站泥沙量作了估算,从而预测三峡工程对长江  相似文献   

2.
基于GIS长江口北港河段冲淤变化的可视化分析   总被引:4,自引:0,他引:4       下载免费PDF全文
利用GIS技术,建立长江口北港1973~2003年间不同时期的水下数字高程模型,以此作为基础资料,通过叠合分析不同时期的水下地形图,得到长江口北港不同时段相对的河床冲淤分布图.分析了长江口北港30年来河道的冲淤变化和演变情况,并计算了河道泥沙冲淤量.结果表明,GIS技术是研究河床演变规律的一种行之有效的可视化方法;北港河段在1973~2003年间整体呈冲刷之势,泥沙冲刷量为1.58亿m3,平均每年冲刷0.05亿m3;北港河床航道稳定性较差,受南、北港分汊口演变的影响,北港河床逐渐演变.洪水在北港河槽演变过程中起着重要的作用.  相似文献   

3.
上海南汇嘴控制工程位于长江口和杭州湾交汇的南汇边滩,是上海市滩涂资源开发利用的重点工程.该海域受径流、强潮和波浪的相互影响,对控制工程的成败起着重要的作用.应用波浪作用下二维潮流数学模型和第3代近岸海浪模式SWAN,建立了二维波浪潮流数学模型.根据2006年8月大潮实测水文资料和大戢山站1979~1998年和杨梅嘴站1997年8月~2001年7月实测波浪资料,对模型进行了全面的验证.结果表明,数值模拟海域潮位和定点垂线流速、流向、波高的计算值与实测值吻合良好.重点研究了圈围工程对附近的长江口南槽、杭州湾北岸、东海大桥、天然液化气管线南汇登陆点及洋山深水港区的水流及波浪的影响和变化.  相似文献   

4.
黄河中游龙潼河段一维悬移质泥沙数学模型   总被引:1,自引:0,他引:1  
建立了适用于黄河中游龙潼河段的一维悬移质泥沙数学模型。利用十年实测水沙资料进行了验证计算,结果表明,实测冲淤量与计算值基本相符。本模型可用于预测不同减水减沙情况下的泥沙冲淤调整过程。  相似文献   

5.
针对海滩侵蚀问题展开了包括滩肩补沙和离岸潜堤在内的海滩修复工程.为评估工程效果,采用Delft3D软件建立了山海关海域的泥沙输运和海床演变模型,使用2015年至2016年的实测资料验证模型.基于验证后的数学模型对工程海域泥沙输运与海床演变变化特征进行分析.结果表明:工程引起了近岸区域泥沙浓度的减小,减小幅度随离岸距离的增大而减小.工程建设前工程海域的侵蚀较为严重,工程的建设大大减小了近岸海域的冲刷深度,有效地保护了工程岸段海滩.工程后冲淤变化幅度第1年最大,然后逐年减少.  相似文献   

6.
基于贴体坐标转换原理,建立了贴体坐标下的河道平面二维非恒定非均匀泥沙数学模型,然后应用ADI法对控制方程进行离散求解.在求解过程中,运用最小能耗率原理来确定河道在冲淤过程中的河宽变化及河岸摆动幅度,弥补了大多数泥沙数学模型只能计算固定河宽下的河床冲淤变化的缺陷.以黄河青铜峡水库为实例,对模型进行了验证计算.计算结果表明,模型能较好地反映库区的水流泥沙运动及河床冲淤变形情况.  相似文献   

7.
南汇嘴-崎岖列岛海域海床演变初步探讨   总被引:1,自引:0,他引:1  
利用2005年春季水文泥沙测量资料和历史海图资料,在分析水动力条件、悬沙和沉积物特征基础上,对海床冲淤量进行计算,探讨了南汇嘴 崎岖列岛海域海床演变的基本规律.得出最近50年来海区呈现淤积减弱和冲刷加强的趋势,而造成这一趋势的原因主要包括海洋动力作用、长江入海泥沙变化以及近岸大型海岸和海洋工程的建设等.  相似文献   

8.
本文采用贴体的正交曲线坐标下的水流运动方程及悬移质平衡输移方程等建立伶仃洋二维非恒定非平衡输沙数学模型。根据实测的泥沙级配资料,文中模拟20世纪70年代伶仃洋的泥沙特性(粘性泥沙与非粘性泥沙运输特性)。在该模型中的泥沙输运的冲淤函数,模型参数选取方面,参考已有的伶仃洋河口研究成果,引用国外成熟公式对模型进行了修订和进一步验证,使之更能反映内伶仃洋的水沙特性。并采用最新的实测地形资料和洪、枯两组水文组合条件进行模拟,将数值模拟结果与伶仃洋的水文站点的实测资料进行验证,其水流、泥沙运动验证精度基本都能达到规范要求。  相似文献   

9.
泥沙输运与海床演变对曹妃甸港口工程的响应特征   总被引:1,自引:1,他引:0  
采用Delft3D软件建立了波流共同作用下曹妃甸海域三维泥沙输运与海床演变数学模型,使用2012年实测潮流和含沙量对模型进行验证.运用验证后的数学模型对2012年曹妃甸工程的泥沙输运和海床演变进行模拟,从而分析泥沙输运与海床演变对港口工程的响应特征,得出以下结论:曹妃甸海域含沙量较低,小于0.2kg·m-3,呈现在平面上为西部高、东部低,滩地高于外海,在垂向上为由表层至底层增大的特点;甸头、西部滩地和东坑坨海域为主要冲刷区,西部深槽和东部老龙沟深槽为主要淤积区.海床一年的冲淤演变总体在0.5m以内,海床是动态稳定的,冲刷率和淤积率均是港口运行可接受的.  相似文献   

10.
基于MIKE21 Flow Model建立双龙河口潮流、泥沙输运及河床演变数学模型,采用实测资料对数学模型进行了验证.通过对不同冲刷方式、开闸流量以及闸门调控过程的调度方案的模拟计算,研究闸门调度方案对闸下河道冲刷效果的影响,分析河道冲淤分布、河道冲刷总量和冲刷效率变化规律.研究结果表明:河道的冲刷总量与开闸流量成正相关,但受河道地形的控导作用,河道各段冲淤分布不均.采用大流量径流冲淤时,连续开闸方式可使河道冲刷效率更高;但采用小流量径流冲淤或纳潮冲淤时,非连续开闸方式可显著提高河道冲刷效率.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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