共查询到19条相似文献，搜索用时 140 毫秒
1.
2.
3.
由于对海岸景观和生态环境影响较小,渗透潜堤被广泛用于沙滩整治修复和侵蚀防护。在波浪水槽中开展物理模型实验,研究潜堤对沙滩剖面演化的影响。采用浪高仪阵列和激光扫描仪采集了水面高程变化和沙滩剖面高程,分析了波浪传播的相关水动力特征,包括波高沿程分布、透射系数、波浪能谱以及非线性指标(偏度和斜度),不同入射波浪和潜堤设置情况时沙滩剖面的变形特征,统计了沙滩侵蚀关键因子(岸线蚀退距离、单宽侵蚀量等),探讨了沙滩侵蚀与波浪条件、渗透潜堤特征参数之间关系,提出了沙滩侵蚀量与渗透潜堤无量纲特征参数的估算公式。研究表明:在堤顶破碎、大孔隙介质阻力和堤前反射综合作用下,入射至近岸沙滩的波浪能量降低,潜堤具有消浪和沙滩侵蚀防护作用;泥沙整体离岸输运,潜堤向岸侧淤积;对于实验考虑的工况,潜堤位置变化对沙滩防护效果的影响较小,堤顶宽度增加更利于消浪和滩面防护,潜堤对于较强的波浪表现出更好的沙滩防侵蚀效果。 相似文献
4.
长江口12.5米深水航道2010年贯通后,发挥了巨大社会经济效益,同时航道回淤量大、维护压力大、维护费用高的问题突出。本研究基于北槽四边界水沙通量观测成果,分析提出了北槽航道回淤泥沙来源;针对回淤原因,在已建减淤工程经验总结的基础上,提出了本次减淤的研究思路,优化了减淤工程方案的比选指标体系;采用三维潮流泥沙数模、清水动床物模、经济技术综合分析等手段,通过"加高范围"、"加高高程"及"加高位置"比选,研究推荐了减淤工程方案。利用实测回淤量分析了工程减淤效果。研究结果表明,南导堤越沙是洪季北槽的重要泥沙来源,对北槽高浓度含沙量场有一定贡献。提出了可通过加高北槽南侧的导堤,实现减少通过南导堤越堤进入北槽的泥沙量,从而减小北槽含沙量水平,同时改善北槽下段流态,降低水沙横向输移,进而降低航道回淤的减淤思路。研究推荐的长江口12.5米深水航道减淤工程为南坝田挡沙堤加高工程及先期工程方案。先期工程位于S4～S9丁坝坝田,在现有南坝田挡沙堤的基础上加高S4～S8区段,并延长至S9丁坝,工程全长约23.8 km,高程+3.5 m。工程于2015年11月开工建设,2016年7月主体工程完工,工程减淤效果显著,2016—2018年年均减淤量约954×105m3/a,近三年已节省航道维护疏浚费用约5亿元。 相似文献
5.
基于非静压数值计算模型,本文系统研究了聚焦波作用下透水潜堤的消波特性,通过设置合理的计算工况,详细分析了波高、堤顶水深、谱峰周期、孔隙率以及堤顶宽度5种因素对透水潜堤消波特性的影响。与此同时,本文将透水潜堤的计算结果同不透水潜堤的计算结果进行了对比分析。计算结果表明:透水潜堤对聚焦波的消减作用要强于不透水潜堤,从而说明,透水潜堤能更有效地降低畸形波对海岸基础设施的影响;波高和堤顶水深是影响潜堤消波特性的重要因素,随入射波高增加、堤顶水深减小,透水潜堤对波浪的消减作用逐渐增强。透水潜堤对长周期波浪的消波效果较差。在本文考虑的孔隙率范围内,孔隙率越大,透水潜堤消波效果越好;当孔隙率为0.4,堤顶宽度为0.612 5 m时,透水潜堤可消减54%的入射波能,比不透水潜堤对入射波能的消减增加36.1%。本文研究结果可为进一步认识透水潜堤的消波特性和海岸防护工程设计提供相应的参考。 相似文献
6.
不同结构形式潜堤上的随机波浪运动 总被引：3，自引：0，他引：3
潜堤在海岸保护和促潍保淤中具有重要的意义。工程效益和经济投入受到潜堤结构形式和高度的影响。基于RANS方程和流体体积（VOF）方法的模型，计算不同潜堤上的波浪运动。潜堤形式包括矩形结构、梯形结构、半圆结构和槽形结构。模拟了不规则波越堤时波浪的破碎特征、破波类型以及波高的变化。通过分析流场和波高分布的变化，得到潜堤上波能散耗的规律，并且得出最优潜堤结构形式。讨论了相对堤顶高度、破碎点位置、相对堤顸宽度、波陡和潜堤结构形式等对波能耗散的影响。 相似文献
7.
潜堤研究中的几个问题 总被引：1，自引：0，他引：1
本文综述现有国内外一些潜堤方面的研究成果,对潜堤设计中的几个问题,如合理的断面型式;合理的堤顶相对标高α/H(α——潜堤堤顶水深,H——潜堤堤前原始波高);消波性能(即波高传递率)n=H_1/H(H_1——潜堤堤后波高,)及潜堤块体稳定重量 W_z 等进行了分析比较并对上述几个问题进行了探讨。 相似文献
8.
针对威海九龙湾岸滩治理工程,进行不同结构型式及不同高程离岸潜堤的物理模型试验。根据物理模型试验的结果,得出离岸潜堤透射系数Kt与主要影响因子的相互关系。得出影响潜堤透射系数最主要的因子为相对堤顶水深(a/Hi),在一定水位条件下,相对堤顶长度(B/L)也能影响透射系数。借助MATLAB数学软件平台,将数据进行回归分析,得出不规则波作用下潜堤透射系数的经验公式,为此类工程设计提供参考。 相似文献
9.
杭州湾深水航道东试挖槽浮泥研究 总被引：4，自引：0，他引：4
本文在对杭州湾深水航道东试挖槽中浮泥进行观测和淤泥特性试验研究的基础上,分析了槽中浮泥产生和消失的规律,认识到浮泥的固结是东试挖槽中泥沙回淤的主要形式。这对研究拟开挖的杭州湾深水航道东段的泥沙回淤规律,确定适航水深和航道维护方案等都有着较重要的指导意义。 相似文献
10.
潜堤对波浪传播变形的物理模型试验研究 总被引：1，自引：0，他引：1
以不可渗透光滑潜堤为研究对象,基于波浪水槽试验,分析了规则波和不规则波通过淹没梯形潜堤时的波浪外部形态变化以及内部能量变化规律。探讨了不同波浪要素(周期、波高、淹没水深)对潜堤附近波高影响的变化规律。同时,探究了潜堤斜坡坡度、堤顶淹没水深对波浪频谱在频域分布的影响。研究结果表明:当波浪通过潜堤时,波浪主频能量衰减,波浪能量由低频向高频移动;潜堤斜坡坡度越大、堤顶水深越小,波浪主频能量衰减越剧烈;波浪通过潜堤后高频波能量占潜堤次生波能量的1%~30%。 相似文献
11.
柔性水囊潜堤由橡胶制成，内部充水，具有结构简单、造价低廉等优点，能较好满足人工岛、跨海桥梁、海洋平台等基础设施建设工程对简单便携、拆装方便的临时防波堤的需求。为了探究柔性水囊潜堤的消波特性，在溃坝水槽内开展溃坝波与半圆柱形柔性水囊潜堤相互作用的试验研究，重点探究柔性水囊潜堤与溃坝波相互作用过程中水位变化特性，并与半圆柱刚性潜堤的性能进行比较；同时分析柔性水囊潜堤内部初始水压和浸没深度等参数对其消波性能的影响。结果表明：柔性水囊潜堤能够用作临时防波堤来衰减波浪；与半圆柱刚性潜堤相比，柔性水囊潜堤在降低溃坝波无量纲最大水位、提高消波性能方面更具优势；内部初始水压是影响柔性水囊潜堤消波性能的重要因素，适当降低内部初始水压，有利于增强柔性潜堤的变形程度，进而增加波能耗散，可获得更好的消波效果；而增加浸没深度即潜深，会使得柔性水囊潜堤对溃坝波的影响程度降低，消波效果减弱。 相似文献
12.
长江河口浮泥形成机理及变化过程 总被引：15，自引：0，他引：15
1976年以来，在长江河口盐水楔和最大浑浊带活动的河道进行了20余次现场观测，本文在现场观测资料基础上，确认长江河口浮泥由细颗粒泥沙组成，中值粒径在8－11.5um,小于2um的粘土占28.18%-36.39%,长江河口浮泥是悬沙在盐水混合环境中絮凝沉降于近义廾风暴潮再悬浮泥沙形成的高浓度浑水层，在成因类型上分为憩流浮泥，盐水楔浮泥和风暴潮浮泥，第1种在涨或落潮转流期低流时形成，规模大，厚度薄，第2种在盐水楔发育时形成，规模较小，厚度较大，第3种在大风后形成，规模大，厚度薄，第2种在盐水楔发育时形成，规模较小，厚度较大，第3种在大风后形成，规模大，范围广，若三者相遇，则浮泥厚度和范围最大，浮泥具有枯季，大小潮秽暴周期变化规律，长江河口河道多的浮泥层，浮泥层的变化与河口拦门沙的冲淤有良好的正相关。 相似文献
13.
《中国海洋工程》2020,(3)
In order to clarify the distribution and variation of silt and fluid mud in the Waiganmen shallow section of the 50000-ton intake channel of the Xiangshan Port, and to understand the influence of the channel excavation on the surrounding flow conditions and the strength of the backsilting, especially the impact of typhoon on the sudden silting of the channel, so as to demonstrate the feasibility and stability of the channel excavation. The fluid mud,hydraulic, sediment and topographic measurements were carried out in the study area, and the thickness of the fluid mud layers, tidal current, sediment and topographic data were obtained. Dual-frequency sounder, gamma-ray densitometer and SILAS navigational fluid mud measurement system were used to monitor the fluid mud, and the results were compared and verified. The adaptability and accuracy of the three methods were analyzed. The SILAS navigational continuous density measurement system and gamma-ray fixed-point fluid mud measurement are used to detect the density, thickness and variation of the fluid mud accurately. Based on the hydrological observation data,the process of erosion and deposition in excavation channel and its influence mechanism are analyzed, and the distribution characteristics and evolution law of siltation in engineering area are given in the form of empirical formula. The research shows that the super typhoon can produce large siltation, which results in sudden siltation of the channel. The tidal current is the main dynamic factor of the change of erosion and siltation of the excavation trench. Under the influence of reciprocating tidal current and excavation topography, the trial excavation trench is silted on the whole. There is fluid mud in the monitoring area of the trench, and the distribution of fluid mud is different in space. The thickness of the fluid mud at the bottom of the trench is generally larger than that outside the trench and the slope of the trench, and the siltation of the trench tends to be slow. The research results can provide scientific evaluation for channel excavation and maintenance, and support for the implementation of the project. 相似文献
14.
《Coastal Engineering》1999,37(2):123-148
The Navier–Stokes equations and the exact free surface boundary conditions are solved to simulate wave deformation and vortex generation in water waves propagating over a submerged dike. Incident waves are generated by a piston-type wavemaker set up in the computational domain. Numerical results are compared with experimental data in order to confirm the validity of the numerical model. The fast Fourier transform and a wave resolution technique are applied to decompose the transformed waves and the higher harmonics. Effects of different parameters on wave transformation and vortex generation are studied systematically. These parameters include the Ursell number, the Keulegan–Carpenter number, the water depth ratio, the Reynolds number, the length aspect ratio of the dike, and the type of dike. 相似文献
15.
在分析射阳港拦门沙航道一期整治工程建设后航道回淤特征的基础上,通过潮流泥沙数学模型分析研究了二期不同整治方案建设后的水流、含沙量及淤积分布特征,论证了不同方案的整治效果。研究表明:现状条件下由于导堤为潜堤,受越堤水流、口门回流等影响,一期工程建设后航道沿程普遍淤积。在一期导堤的基础上将导堤加高后有利于减小口门段航道淤积;将导堤延长后,淤积最严重的部位年淤强度有所减小,但在新的口门附近航道淤积仍然较严重;将口门宽度缩窄后,口门附近的淤积强度有所减小,但幅度有限;在航道内增加丁坝后,口门段泥沙淤积强度有所减小,但对改善中段航道淤积有限。 相似文献
16.
利用二维水动力数学模型模拟胶莱人工河道潮流运动,并分析了胶州湾湾口设置潜堤前后胶莱人工河道水质点的运动轨迹和水位变化过程。结果表明,开通胶莱人工河道能够使黄海的胶东湾海水向渤海的莱州湾输运,但不设置潜堤时从胶州湾到莱州湾的海水输运平均流速较小;设置潜堤后胶州湾水位高于莱州湾水位的时间变长,从黄海到渤海之间的水体输运能够得到加速。计算结果还表明,潜堤顶部与平均水面距离较小时,黄、渤海之间水体输运较快。 相似文献
17.
Fluid mud dynamics in the Weser estuary turbidity zone tracked by high-resolution side-scan sonar and parametric sub-bottom profiler 总被引：1，自引：0，他引：1
Kerstin Schrottke Marius Becker Alexander Bartholomä Burghard W. Flemming Dierk Hebbeln 《Geo-Marine Letters》2006,26(3):185-198
Fluid mud in estuarine turbidity maximum zones (TMZ) can pose considerable navigation risks due to potentially substantial reductions in nautical depth, coupled with an inherent difficulty of detection by conventional echo-sounders. Despite intensive research efforts, however, our knowledge about the spatial and temporal dynamics of fluid mud is still not sufficient. In this study, the combined use of a side-scan sonar (Sportscan®, Imagenex) and a parametric sub-bottom profiler (SES-2000®, Innomar Technology GmbH) has proved successful for high-resolution fluid mud detection and volumetric quantification in an estuarine environment. In 2004 and 2005, repeated surveys were conducted in the navigation channel of the upper meso- to lower macrotidal Weser estuary TMZ (German North Sea coast) at different tidal stages and river discharges. Current velocity data were simultaneously collected by 1,200-kHz broadband ADCP (RDInstruments) measurements. Ground-truthing was carried out by means of grab sampling and gravity coring, adapted to fluid mud conditions. It was found that fluid mud occurrence in the Weser estuary is highly variable on time scales of a few hours and spatial scales of several metres. The riverbed is characterised by sand and mud deposits, and a complex morphology including subaqueous dunes and smooth bed deposits intermittently overlain by fluid mud. Thus, a continuous, coherent fluid mud body covering the entire TMZ riverbed was not observed. Rather, spatial distribution was patchy and highly dependent on suspended particulate matter (SPM) concentrations in the water column, as a result of which local fluid mud deposits varied in thickness from centimetres to metres. The formation of fluid mud was largely restricted to slack water, although slack-water conditions were not necessarily associated with large-scale fluid mud appearance. Advective SPM transport of resuspended fluid mud seems to be the most plausible explanation for the high spatial variability observed, even between two successive tides. The amount of fluid mud deposited and resuspended in the course of a tidal cycle can reach several 10s of tons even in small riverbed depressions. 相似文献
18.
A two-dimensional analytical solution is presented to study the reflection and transmission of linear water waves propagating past a submerged horizontal plate and through a vertical porous wall. The velocity potential in each fluid domain is formulated using three sets of orthogonal eigenfunctions and the unknown coefficients are determined from the matching conditions. Wave elevations and hydrodynamic forces acting on the porous wall are computed. Reflection and transmission coefficients are presented to examine the performance of the breakwater system. The present analytical solutions are found in fairly good agreement with the available laboratory data. The results indicate that the plate length, the porous-effect, the gap between plate and porous wall, and the submerged depth of the plate all show a significant influence on the reflected and transmitted wave fields. It is also interesting to note that the submerged plate plays an important role in reducing the transmitted wave height, especially for long incident waves. 相似文献