沙质海岸突式建筑物下游离岸堤防护的试验研究

本文对采用离岸堤作为保护侵蚀海岸的措施进行了试验研究。通过模型试验,对离岸堤的淤积性能有了进一步的认识。文中还讨论了离岸堤堤后的淤积规律,提出了连岛坝及稳定沙嘴的形成条件,并探讨了透浪式离岸堤的一些基本问题。     

季冻区河流岸滩崩塌机理及其数值模拟研究进展

岸滩侧蚀崩塌现象广泛分布于世界各大江河之中,是一种危害较大的自然灾害.季冻区河流受水动力-冻胀/冻融耦合作用,岸滩崩塌机理复杂,影响因素众多,其崩塌机理研究对河岸防护和河流综合治理具有重要意义.从岸滩崩塌机理与力学模式、岸滩崩塌及河床冲淤交互作用数值模拟、典型季冻区河流(松花江及黑龙江)河道演变研究三个方面,对当前该领...     

建立稳定海岸系统 控制海岸冲刷

一、前言近年来,随着河川流域的开发和沿岸土地的利用,海岸冲刷已成为众所周知的重大课题。对自然环境的保护问题,已引起各方面的高度重视。作为海岸防护的对策,很早就开始建造大量的护岸工程,如丁坝及离岸堤等各种海岸建筑物。尽管建筑经费在逐年增长,但就现状来看,各种建筑物尚未充分发挥作用。很久以前,地貌学家们研究了地貌的特性,他们发现:沙质海岸与入射波向线垂直的海岸,称为稳定海岸,并把它命名为“之”形海湾或“勾”状海湾。尤其是本文     

堤岸防护的类型及其应用

江、河、海堤防的堤脚、滩岸及其防护工程是密不可分的,"保堤必须固岸"是一条普遍经验.由于堤脚和岸滩在受水流、风浪、潮汐等的侵袭、冲刷情况下经常造成破坏,对这类堤岸进行防护,以控制、调整水流,稳定岸线,保护堤防的安全.     

波浪通过斜坡上潜堤的波能演化实验研究

潜堤是防止海岸侵蚀的常用护岸建筑物,准确的掌握潜堤前后波浪的传播变形规律十分必要.该文以斜坡上梯形潜堤为研究对象,基于波浪水槽实验,通过谱分析探求线性波、非线性波、非规则波通过斜坡上潜堤内部组成能量的变化规律,分析相同的入射波情况下波浪倍频能量演变与堤顶水深大小的关系,得出堤顶水深越小主频能量衰减越大的规律.同时,比较研究线性波与非线性波作用下潜堤前后波能的变化,发现非线性波高倍频能量产生更加剧烈.     

围头湾北岸侵蚀带护堤建设探讨

该文根据调查研究结果,分析围头湾北岸岸滩侵蚀状况及海堤毁坏原因,建议在受侵蚀严重的白潘海堤堤外适当位置试验研究修筑潜堤,以达到消浪、促淤、护堤的作用。     

粉砂质海岸促淤计算及预测研究

根据粉砂质海岸的特点及泥沙的悬移、沉降特性,对现有水体挟沙力公式进行改进,给出了基于潜堤透射系数的粉砂质海岸促淤工程淤积计算方法,该方法可对粉砂质海岸围垦促淤、保滩促淤工程的效果进行简单预测.     

沙质海岸岸滩坡度的确定

确定沙质海岸的岸滩坡度,对海岸区的开发利用,特别是沿海港口建设具有较大的现实意义。在前人研究的基础上,本文试图对现有的原体观测和模型试验数据进行分析与概括。通过分析表明,海岸的岸滩坡度是海岸沉积物粒经和比重的函数,也是海岸区的深水波长、波高以及波陡的函数,从而提出一个适用于原体、模型及水槽试验的岸滩坡度的经验关系式。并从这一关系式出发,导得岸滩坡度相似条件下确定模型砂粒径的公式,为试验选砂提供参数。     

不同海塘提标加固方法波浪模型试验研究

为评价不同海塘提标加固方法的消浪效果和经济性,采用波浪物理模型试验,针对新建挡浪墙、后置挡浪墙、铺设块石和构筑潜堤4种提标加固方法进行研究。试验结果表明:在现有海塘顶构筑新挡浪墙可以显著降低越浪量,越浪量随着挡浪墙高度增加而减小,同时挡浪墙位置后移也同样能使越浪量减小;在塘前铺设大块石消浪,越浪量能够显著降低,但对块石自身稳定性和块石顶高程要求较高;使用海域范围有限的情况下,构筑离岸近、顶宽窄的潜堤并不能起到很好的消浪效果,且潜堤工程量较大,采用该方法提标加固海塘需要进行研究。     

风暴潮对港口水陆域及航道安全影响研究——获2011年度中国航海学会科学技术奖一等奖

"风暴潮对港口水陆域及航道安全影响研究"是交通运输部"十一五"重大专项《离岸深水港建设关键技术研究(200632800003)》的课题三,课题于2006年10月立项,2010年5月通过交通运输部科技司组织验收鉴定.针对风暴潮对离岸深水港建设中码头高程、航道骤淤机理及整治方法和预报技术的要求,课题全面揭示了细粉沙、淤泥粉砂质海岸外航道骤淤机理、波浪破碎条件下破波区泥沙垂向输送机理,提出了波浪、潮流     

盐城市侵蚀性海岸防护设计

介绍盐城市侵蚀性海岸防护概况,以及海岸防护设计中应正确处理的2种关系,即宏观蚀退和微观保护的关系以及保堤、保脚、保滩的关系。对常见的防护、保滩(促淤)工程的结构形式及其特点进行总结。以盐城市海岸侵蚀最为严重的滨海县六合庄为例,进行典型岸段海岸防护效果分析。指出:在盐城市侵蚀性海岸防护设计中,应在宏观蚀退条件下构建侵蚀性海岸整体防护体系,保护沿岸地区工程的安全;工程措施不能在宏观上改变海洋与地质条件,但能够在局部改善水沙条件,起到消浪与阻止沿岸流冲刷的作用;保堤必须保脚,保脚必须保滩。     

Coastal geomorphic response to seasonal water-level rise in the Laurentian Great Lakes: An example from Illinois Beach State Park,USA

Hydrodynamic processes, such as fluctuating water levels, waves, and currents, shape coastlines across timescales ranging from minutes to millennia. In large lacustrine systems, such as the Laurentian Great Lakes, the role of water level in driving long-term (centuries to millennia) coastal evolution is well understood. However, additional research is needed to explore short-term (weeks to months) beach geomorphic response to fluctuating water level. Developing a process-focused understanding of how water level fluctuations shape coastal response across these shorter time scales is imperative for coastal management. Here, we present measurements of geomorphic response along a lacustrine beach ridge plain to seasonal water level fluctuations during a decadal high-stand in Lake Michigan water level. Frequent topographic change measurements revealed high spatial and temporal variability in geomorphic response to rising lake level. Sites immediately downdrift of shore protection began to erode immediately as lake level increased. The co-occurrence of peak seasonal lake levels and a modest increase in wave energy resulted in erosion and overwash at sites that resisted erosion during the initial seasonal rise in lake level. None of the sites in this study returned to their initial morphology following seasonal lake level rise. Given that peak water levels were nearly identical in 2017 and 2018, yet the majority of erosion at our sites occurred in 2017, we postulate that erosion associated with seasonal lake level rise is primarily a function of the change in annual maximum water level from year to year, rather than solely the elevation of the water level.     

Influence of near-shore marine structures in a beach nourishment project on tidal currents in Haitan Bay,facing the Taiwan Strait

The Longfengtou Beach in the Haitan Bay,located in Fujian Province of China and facing the Haitan Strait,has been suffering severe erosion due to the construction of seawalls.A simple beach nourishment project implemented has not achieved the anticipated beach restoration.Thus a practical solution has to rely on a combination with near-shore marine structures.In this study,a 2-D calibrated flow model is set up to investigate the effects of three different layouts of near-shore marine structures on the tidal current.It is shown that the breakwaters situated in both the north and south ends play a vital part in the protection against erosion.The offshore breakwaters can serve as a barrier to obstruct the current circulation then reduce the current velocity.The groyne linking the Guimo islet and the coast significantly reduces the south-to-north water exchange through the channel and redirects the current direction nearly perpendicular to the north breakwater,which cuts off the longshore transport that may have a negative influence on the beach,especially,the northern part.It is also noted that the monsoon at the site with different directions increases the current velocity.In general,proper layouts of marine structures can reduce the current velocity thus lead to less intense sand transport near the beach.     

基于定量分析的江苏中部海岸线动态监测

江苏沿海中部外侧分布着规模宏大的辐射沙脊群,近岸属于典型淤长型淤泥质海岸,定量监测海岸线的动态变化对海岸带潮滩资源的开发和保护具有重要意义。以1979~2012年间6个时期的Landsat和HJ1A/B遥感影像为数据源,利用遥感和GIS技术对射阳河口至北坎尖之间的海岸线变迁和潮滩围垦动态进行定量分析。结果显示:1979年以来研究岸段总体向海推进显著,海岸线向海推进过程中,岸线长度和曲折度总体呈减小趋势;岸线推进速率均呈先增大后减缓的趋势。研究结果可为江苏沿海滩涂资源的开发和保护提供参考,亦可供江湖水库岸线利用与保护管理借鉴。     

第四届发展中国家海岸和港口工程会议论文概貌

采用检索方式介绍第四届发展中国家海岸和港口工程会议论文概貌和特点。本届会议论文收集论文１８５篇，涉及海岸动力，海岸综合开发和管理，港址选择，河口演变，航道疏浚、回淤和维护，防波堤和港工结构，海岸和港口工程对环境的影响和保护等领域。广泛应用数学模型，重视现场观测，改善试验和量测技术是海岸工程研究的发展趋势。本文对多数文章的内容特点作了介绍。     

江苏省条子泥滩涂匡围相关问题研究

条子泥滩涂匡围对于未来江苏沿海滩涂资源的大规模开发和利用具有重要的示范效应。针对条子泥滩涂匡围工程,从潮滩一沙洲系统稳定性、匡围布局的合理设置、水资源综合开发利用、环境影响评价及经济影响评估等方面就条子泥匡围工程若干受到广泛关注的问题进行了探讨和研究,提出解决条子泥围垦与保护关键技术的研究对江苏沿海滩涂资源的全面开发和利用具有巨大的示范意义和促进作用。     

基于局部拟合法的低能沙质海岸比尺设计

在波浪作用下的泥沙运动过程中,由于泥沙粒径的大小会影响到波浪边界层的紊动状态,以及泥沙沉降时绕流的紊动状态,进而影响其沉降和起动的规律,故波浪作用下的沙质海岸动床物理模型的比尺向来是一个复杂问题,其设计需要对各种因素进行衡量与取舍。而对于我国渤海、黄海沿岸常见的沙质海岸,其粒径范围决定了沉降时的绕流处于层流、紊流的过渡状态,沉降规律更为复杂,使其比尺设计更加困难。针对我国黄、渤海沿岸常见的低能沙质海岸波浪动床试验的泥沙比尺设计问题,探讨了适用于低能沙质海岸的比尺准则,剖析了比尺设计的难点,并提出了适用于一定泥沙粒径范围内比尺设计的局部拟合法。基于局部拟合法,针对低能沙质海岸剖面波浪动床试验,提出了相应的泥沙起动、沉速比尺关系式。     

Great lakes urban pocket-beach dynamics: A GIS-based analysis of infrastructure-design influences on geomorphic development

Chicago’s lakefront beaches experienced inundation and coastal erosion when Lake Michigan’s mean annual water level rose by >1.5 m between 2013 and 2019. Understanding beach geomorphic response to this type of lake-level event is important, as future climate predictions call for a continuation of decadal oscillatory patterns. A GIS-based study of beach change was conducted along the city’s urban lakefront, where sand is embayed by groins, jetties, and revetments. Morphologic changes associated with the most recent decadal lake-level rise were evaluated in context of the surrounding infrastructure. Beach morphometrics, derived from historical aerial images and available LiDAR products, were compared against the characteristics of the fixed urban infrastructure. Overwash volumes associated with an ～1 m-rise in lake level scaled well with beach size (R² = 0.88), suggesting that the creation of new sediment accommodation and its spatial distribution along the urban lakefront during lake-level rise is an important control on beach morphodynamic behavior. Overwash patterns were influenced by embayment orientation and groin characteristics. Counterclockwise beach rotation of up to 21° occurred in places where shorelines were exposed to the open lake. More tightly enclosed beaches retreated more uniformly along strike due to passive inundation of terrain with lake-level rise. Our insights provide managers with useful information on key beach behavioral patterns and how they are influenced by infrastructure design, allowing for the possibility of mitigation strategies to be emplaced in anticipation of future lake-level oscillations.     

Punctuated decadal morphodynamics and coupled vegetation succession along a nontidal,wave-dominated Great Lakes barrier spit,Gull Point,Lake Erie,U.S.A.

The Presque Isle Peninsula is a compound barrier-spit system perched atop a recessional moraine along Lake Erie’s southeastern coast. Its distal terminus, Gull Point, has grown to an extent of around 0.6 km² since the early 1900s, promoted by beach nourishment along the peninsula proper and later influenced by a change in local hydrodynamic regime following breakwater installation near the attachment point. This coastal setting has set the stage for an analysis of ridge landform- and vegetation-succession dynamics using historical aerial images, a series of high-resolution LiDAR datasets, transect/quadrat surveys of vegetation, and increment core dates of tree cohorts on dune ridges separated by swales and lagoons. The general evolutionary model is one of punctuated landform growth to the east by lateral accretion, interspersed with erosional events and ridge recurving towards the backbarrier. Eastern cottonwood (Populus deltoides), with its minimally provisioned wind- and water-dispersed seeds, colonizes the margins of newly deposited sand ridges as discrete cohorts, and dominates the tree stratum of Gull Point. These cohorts are increasingly mature moving from distal to proximal zones, and consistently reflect the temporal sequence of ridge morphology. Vegetation communities, representing a primary successional chronosequence, are delineated into four phases extending back to the 1950s, which are roughly demarcated by erosional ridgelines of topographic prominence, revealing a tight coupling of lake-level trends, geomorphology, and vegetation dynamics. This provides coastal researchers with a means of understanding landform-age relationships across structurally complex strand areas for which age-relationships cannot be ascertained by aerial photographic records alone.