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The paper focuses on the numerical simulation of erosion of plane sloping beaches by irregular wave attack in three wave flumes of different scales. One of the prime objectives of the tests was to provide a consistent data set for the improvement of numerical beach profile models. A practical application of this research with wave attack on plane sloping beaches is the erosion of the plane beaches after nourishment. Three models (CROSMOR, UNIBEST-TC and DELFT3D) have been used to simulate the flume experimental results focusing on the wave height distribution and the morphological development (erosion and deposition) along the beach profiles. Overall, the model predictions for wave heights show consistent results. Generally, the computed wave heights (Hrms and H1/3) are within 10% to 15% of the measured values for all tests (under-prediction of the largest wave heights close to the shore). The three models can simulate the beach erosion of the wave flume tests (erosive tests) reasonably well using default values of the sand transport parameters. The model performance for the accretive tests is less good than that for the erosive tests. A practical field application of this research is the erosion of nourished beaches, as these beaches generally have rather plane beach slopes immediately after nourishment. Various graphs are given to estimate the beach erosion of nourished beaches. 相似文献
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由于自然因素和人类活动的影响等原因,世界很多海滩经受着侵蚀和破坏。而利用人工养护工程来保护和恢复海滩具有养护效果较明显、干滩面积明显增加以及不破坏环境景观的优点,目前得到越来越多国家的认可。国外由于养滩历史较久,养滩工程后的监测和质量评价不仅开展得早,而且已经成为工程的一个重要部分。评价指标已经比较完善,甚至有些国家已经将养滩效果评价列入法规框架之中。我国的海滩养护工程在十几年前才开始,虽然工程量逐年增长,但是对海滩养护工程施工后的工程监测和工程评价却较少涉及。本文对美国、荷兰、英国、丹麦以及我国等国家的海滩养护工程的工程评价工作进行总结,从而提出适用于我国工程特点的养滩工程质量评价因子和方法。 相似文献
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Torrey Pines State Beach, a site with large seasonal fluctuations in sand level, received a small shoreface beach fill (about 160,000 m3) in April 2001. The 600 m-long, flat-topped nourishment pad extended from a highway riprap revetment seaward about 60 m, terminating in a 2 m-tall vertical scarp. A 2.7 km alongshore span, centered on the nourishment region, was monitored prior to the nourishment and biweekly to monthly for the following 2 years. For the first 7 months after the nourishment, through fall 2001, significant wave heights were small, and the elevated beach fill remained in place, with little change near and above Mean Sea Level (MSL). In contrast, the shoreline accreted on nearby control beaches following a seasonal pattern common in southern California, reducing the elevation difference between the nourished and adjacent beaches. During the first winter storm (3 m significant wave height), the shoreline retreated rapidly over the entire 2.7 km survey reach, forming an alongshore-oriented sandbar in 3 to 4 m water depth [Seymour, R.J., Guza, R.T., O'Reilly, W., Elgar, S., 2004. Rapid erosion of a Southern California beach fill. Coastal Engineering 52 (2), 151–158.]. We show that the winter sandbar, most pronounced offshore of the nourishment, moved back onto the beach face during summer 2002 (following the usual seasonal pattern) and formed a wider beach above MSL at the site of the original nourishment than on the control beaches. Thus, the April 2001 shoreline nourishment was detectable until late fall 2002, persisting locally over a full seasonal cycle. In an extended 7-year time series, total sand volumes (summed between the back beach and 8 m water depth, over the entire 2.7 km reach) exhibit multi-year fluctuations of unknown origin that are twice as large as the nourishment volume. 相似文献
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台风"艾利"对福建沙质海滩影响过程研究 总被引：6，自引：0，他引：6
通过对福建沙质海滩地形地貌现场调查,对比分析0418号台风“艾利”登陆福建前后各沙滩剖面的蚀淤变化,探讨了福建沙滩对台风“艾利”响应规律。研究结果表明,2004年8月底台风“艾利”过境期间,福建沿海砂质海岸显出了较强烈的地貌响应。沙滩剖面地形变化,冲淤相间,以冲蚀为主;后滨沙丘蚀退、滩肩蚀低、岸线向陆迁移是地貌响应的主要特征;沙滩沉积物的总收支趋于亏损。不同海岸类型的沙滩剖面对台风“艾利”的响应特征不同。岬湾型沙滩剖面地貌响应以前滨滩面侵蚀为主要特征。夷直型的长乐江田下沙剖面,对“艾利”台风的主要地貌响应特征为后滨沙丘、高潮带侵蚀,岸线后退超过16m,出现高度近1 m的直立侵蚀陡坎。沙坝-泻湖型沙滩剖面冲淤变化的主要特征是中潮带形成次一级沙坝。各沙滩的地貌风暴效应有自北往南依次减弱的趋势。 相似文献
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Balaena Bay, Wellington Harbour, New Zealand, has a small pocket beach that was covered originally by pebbles and cobbles. In February and October 1982, the beach was nourished with sandy granular gravel, the stability of which was monitored until February 1984. Although isolated from oceanic swell, the new beach readily responded to locally generated wind waves which induced both northwards and southwards longshore drift. The net effect was erosion of the southern beach, aggradation over the central beach, and minor fluctuations at the northern end. Yet despite this mobility nearly all the nourishment sediment was retained in the littoral zone. Beach volumes, calculated for each survey, varied little and sediment distribution patterns revealed negligable transport of nourishment sediment to adjacent beaches and offshore areas. Stability is further confirmed by compositional data which record no preferential loss of the sandstone, argillite, and quartz components. The only compositional changes were the incorporation into the new beach of small (< 10%) quantities of sediment derived from the old beach surface and from biogenic productivity. 相似文献
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基于海洋站潮位观测和中国沿海海平面变化影响调查等数据,分析了辽东湾沿岸海平面变化及海岸侵蚀状况,并定量评估了未来海平面上升情景下,辽东湾两岸典型沙质海岸侵蚀影响和沙滩养护投入。分析预测和评估结果表明:1980-2017年,辽东湾沿海海平面上升速率为3.0 mm/a,其中辽东湾东岸沿海海平面上升速率明显高于西岸。2009-2017年,辽宁营口白沙湾、绥中网户、绥中南山港和绥中团山气象观测场岸段后退和下蚀较为严重,部分岸段滩肩蚀退达2～3 m/a。预计2100年,辽东湾沿海海平面上升幅度在20～48 cm之间,由海平面上升引发的辽东湾海岸侵蚀土地损失为23.1 km2,土地经济损失为1410万元。为减缓海岸侵蚀,旅游沙滩和一般沙滩养护总投入分别为11亿元和46亿元,全岸段养护成本较高,应选取旅游沙滩等重点岸段进行养护。 相似文献
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文章基于2022年春、秋季开展的龙岐湾沙滩资源调查数据，分析较场尾沙滩、大塘角沙滩、黄泥湾沙滩和桔钓沙沙滩的剖面特征、沉积物粒径和裂流发生情况。研究结果表明：4处沙滩剖面的坡度秋缓春陡，剖面受风浪和潮汐直接作用时坡度变化大，受遮蔽时坡度变化小，整体呈冬春淤积、夏秋侵蚀；沙滩沉积物以中砂、粗砂和砾石为主，粒径变化不大；沙滩均无明显裂流发生，为低风险等级。建议开发沙滩旅游应考虑季节性的补沙方案，开展围垦养殖和海岸工程应注意削弱ESE向和SE向的波浪作用。 相似文献
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人工海滩研究进展 总被引：11，自引：0，他引：11
海滩是激浪作用下泥沙在激浪带的堆积,是海岸带最活跃的地貌单元。近年来,由于世纪性的海平面上升,侵蚀型海滩范围扩大,侵蚀加重,海滩宽度变窄、坡度变陡和滩面物质粗化等问题日益严重,引起了广泛关注,亦成为海岸工程研究的热点课题之一。几十年的工程实践表明,海滩喂养与人工海滩是当前防护海滩侵蚀最有效的措施,并已为欧、美、日等国广泛应用。利用海岸地貌学原理方法,借鉴模拟环境条件类似的周边自然海滩的形成和演变规律,合理的设计海滩物质的颗粒大小和组成,海滩的坡度、高度、宽度以及填砂范围等关键参数,能够有效地使人工海滩更快的达到平衡状态并维持其稳定。在海滩的娱乐休闲功能在国际范围内日益受到重视的今天,这一方法在海岸工程应用上具有重要的现实意义。 相似文献
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热带气旋前进方向两侧海滩风暴效应差异研究--以海滩对0307号台风"伊布都"的响应为例 总被引：11，自引：0，他引：11
在0307号台风“伊布都”(Imbudo)袭击华南沿海前后,对相距约300km的高栏岛飞沙湾(位于气旋前进方向右侧)和水东港下大海(位于气旋前进方向左侧)的固定海滩剖面地形及滩面沉积物进行了对比调查。调查结果表明,右侧海滩地形受台风暴浪冲击发生剧烈变化：后滨陆侧堆积,后滨向海侧及前滨滩面侵蚀(单宽侵蚀量达55m^3／m,平均海面(MSL)位置蚀退13m,岸线位置蚀退5m),以致剖面类型由滩肩式断面向沙坝式断面转变,表现出了海滩对台风做出快速响应;而左侧海滩剖面地形基本保持原状,虽也略呈侵蚀,但冲淤变化不大,表现为对台风做出迟缓响应。同时,从动力、滨海输沙、滩面沉积物变化和海岸地貌等方面对两侧海滩明显差异的风暴效应的机制进行了探讨。 相似文献
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In the light of global warming and sea level rise there are many coastal beaches that suffer from erosion. Beach nourishment has become a common practice to maintain the sediment balance on a shore-face. In this paper, a three-dimensional numerical model for evaluating long-term impact of beach nourishment projects has been developed. The model addresses the longstanding complex issue of coastal morphology and sediment grain size distribution from an unconventional angle, which exploits the strong links between grain size distribution and the prevailing transport direction of each sediment constituent under ‘average’ wave and storm action. The present model predicts the redistribution of nourished sediment according to the subtle clues implied by equilibrium distribution curves and latest coastal wave transformation theories. After verification against recent field observations in Terschelling, The Netherlands, the model was used to predict long-term effects of different beach nourishment strategies. It was found that: (a) given the source sediment available in Terschelling the tactics of large volume and less frequent implementation are better than otherwise; and (b) from a pure engineering point of view, waterline nourishment outperforms offshore trough nourishment.The model offers an additional tool for coastal engineers to evaluate the feasibility, effectiveness and the optimization of dumping locations for beach nourishment projects. It is also a useful tool for stratigraphic modelling of shallow-marine sedimentation in conjunction with sea level changes. 相似文献
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我国硬式护岸、渔港工程和人工岛等3类典型海岸工程对相邻海滩有显著影响.本研究以泉州青山湾护岸、泉州崇武中心渔港、海口南海明珠人工岛等建设前后海滩变化为例,开展对海滩岸线形态及部分典型剖面形态的对比分析.结果表明,临海硬式护岸岸前海滩发生明显下蚀,护岸下游海滩岸线侵蚀后退,发育侵蚀热点,剖面伴有下蚀;渔港工程拦沙堤附近岸线局部淤涨,下游海滩岸线大范围侵蚀后退,出现侵蚀热点,侵蚀热点处剖面明显下蚀;人工岛后波影区内海滩淤积,形成沙岬或连岛沙坝突出体,突出体两侧岸线均发生不同程度侵蚀后退.通过分析典型工程案例,探讨了3类海岸工程对相邻海滩的影响方式、影响尺度和原因,对比分析不同类型海岸工程对相邻海滩的负面影响,可为海岸工程建设管理和海滩保护提供参考. 相似文献
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大量工程实践表明,海滩养护是当前抵御海岸侵蚀的常见措施。通过人为地向海滩补充沙源,以达到海岸防护、修复沙滩等目的。本文建立了XBeach一维海滩剖面演变数值模型,并与物理模型试验结果进行对比验证;计算常浪条件下不同方案补沙后海滩剖面达到平衡状态的速率;通过对比补沙工况与未补沙工况的风暴后剖面,分析风暴作用下的防护效果。结果发现,补沙量较大时,沙坝向海侧位置补沙在常浪条件下补沙效率高于滩肩补沙,在风暴条件下防护效果优于滩肩补沙。此次研究对于在实际海滩养护过程中节约施工成本、提高施工效率有着重要意义,同时对于评估沙滩养护工程效果有一定的参考价值。 相似文献
14.
不同沉积物养护海滩对台风响应的差异性研究 总被引：2，自引：2，他引：0
本文通过对厦门天泉湾人工卵石滩和会展人工沙滩在1614“莫兰蒂”超强台风影响前后的典型剖面监测，结合水文动力要素的观测和数值模拟，计算了台风影响过程的波浪场、总水位，分析了剖面形态和台风过程的剖面平均变化量。结果表明，强潮海岸人工卵石滩与人工沙滩对台风响应的特征明显不同，人工卵石滩横向上大部分卵石向岸输移堆积，滩面侵蚀，滩肩堆积形成更高的风暴滩肩，坡度明显变陡。而人工沙滩则表现为明显的沉积物离岸输运，上部滩面侵蚀，下部滩面淤积，滩面坡度明显变缓，受台风登陆后的强烈向岸风作用，滩肩顶有所夷平，滩肩高度变化很小。海滩滩肩在台风过程中是否侵蚀与台风登陆和影响过程的总水位(天文潮、风暴增水、波浪爬高)密切相关，两个人工海滩的风暴响应模式均为冲蚀；台风影响过程中，波浪能量相对强、滩面坡度相对陡的人工卵石滩比人工沙滩的剖面平均变化量小，对于台风的响应程度小，在强侵蚀高能海岸采用砾石等粗粒径沉积物进行海滩养护是减缓砂质海滩侵蚀的一种有效手段。 相似文献
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海岸侵蚀是沿海各国面临的共同问题,海滩养护是当前砂质海岸保护的最佳手段,在全球范围内得到广泛应用。本文回顾了海滩养护技术的发展历程,总结了世界范围的海滩养护实践,分析各国海滩养护理念上存在的差异。以研究文献为基础,总结归纳了平面和横向剖面的补砂方式、辅助工程技术和海滩模型预测等方面的海滩养护技术研究进展,并在此基础上提出了海滩养护的未来发展趋势:①针对复杂海岸的海滩养护应用拓展;②基于沉积物管理的海滩养护修复;③从地貌系统到生态系统全面考虑的海滩养护技术;④全球砂源赤字条件下的海滩保护和修复思路。 相似文献
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A standard assumption in coastal engineering is that the porosity of natural beach sand (non-cohesive) is 40%. However, is this assumption correct for all beach sand? This paper proposes an accurate and simplified method to assess changes in sand porosity after beach nourishment by means of in-situ density surveys through a nuclear densimeter. This novel application has been applied to different beaches in the southwest of Spain according to the tidal range, grain size and beach morphology in several terms. General results show that sand porosities range from 25.6% to 43.4% after beach nourishment works. This research can be considered a support tool in coastal engineering to find shifting sand volumes as a result of sand porosity variability after beach nourishment and later marine influence. 相似文献
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Estimation of erosion volumes for adequate dry beach buffer zones is commonly estimated on the basis of a single extreme event, such as the 1 in 100 year storm. However, the cumulative impact of several smaller, closely spaced storms can lead to equal, if not more, dry beach loss, but this is often not quantified. Here we use a calibrated model for dune erosion, XBeach, to hindcast the cumulative erosion impact of a series of historical storms that impacted the Gold Coast, Queensland region in 1967. Over a 6-month period, four named cyclones (Dinah, Barbara, Elaine, and Glenda) and three East Coast Lows caused a cumulative erosion volume greater than the predicted 1 in 100 year event. Results presented here show that XBeach was capable of reproducing the measured dry beach erosion volume to within 21% and shoreline retreat to within 10%. The storms were then run in 17 different sequences to determine if sequencing influenced final modeled erosion volumes. It is shown that storm sequencing did not significantly affect the total eroded volumes. However, individual storm volumes were influenced by the antecedent state of the beach (i.e. prior cumulative erosion). Power-law relationships between cumulative energy density (∑ E) and eroded volume (∆V) as well as cumulative wave power ((∑ P)) and eroded volume (∆V) both explained more than 94% of the modeled dry beach erosion for the 1967 storm sequences. When the relationship was compared with observed and modeled erosion volumes for similar beaches but different storm forcing, the inclusion of pre-storm beach swash slope (βswash) in the parameterization was found to increase the applicability of the power-law relationship over a broader range of conditions. 相似文献
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Shoreline Change Modeling on Emergency Beach Nourishment Project on West Beach of Beidaihe, China 总被引：3，自引：0，他引：3
By use of a shoreline-change numerical model (GENESIS) based on one-line theory, a preliminary modeling study on shoreline changes caused by a beach nourishment project in Beidaihe, China, is presented in this paper. Firstly, the GENESIS model is verified and model sensitivity to the major parameter changes is discussed by simulating a hydraulic model test. The beach nourishment project, after that the shoreline change is kept being monitored, is a small-scale emergency one carried out to use two bathing places on the west beach in the summer, 2008. In this paper the shoreline changes caused by the beach nourishment project are modeled by the GENESIS model, and the computed results fit well with the measured shorelines. With the same model and parameters, a long-term performance of the project is predicted, and the result shows that the bathing places only can be suitable for bathing in 2 to 3 years without subsequence nourishment project. Therefore, it is proposed to nourish the beaches in time to keep the service life of the beach in recent years and carry out the beach nourishment project for the whole west beach as soon as possible. 相似文献
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海岸侵蚀已成为砂质海岸重要灾害之一,世界各国都致力于海滩防护。荷兰由于地势低洼,在护滩工程中进行大量尝试,于2011年在代尔夫兰海岸开展创新性人工育滩工程即Sand Motor,单个工程补沙总量达2.15×107 m3。持续监测结果显示,工程建成后的沙滩形态与模拟结果基本吻合,沙量损失速度低于预期。阶段性评价结果表明,Sand Motor通过波浪、海流等向海滩缓慢输沙,稳定海岸沙滩和海岸沙丘,具有防护效果显著、成本较低、使用寿命长、增加海岸利用等优点,值得我国借鉴。 相似文献