人工海滩研究进展

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。     

砾石海滩剖面设计及其稳定性模型试验研究

海滩剖面设计参数确定和稳定性评价是设计阶段确保海滩养护工程质量的重要指标。针对大连凌水湾砾石海滩养护工程,综合采用Dean平衡剖面原则和剖面类比法进行剖面设计,确定了填砂中值粒径、施工坡度、滩肩前沿高程和滩肩宽度等设计参数;结合物理模型试验进行了剖面形态稳定性分析,研究了海滩在不同波浪和水位作用下的剖面形态演化过程,试验结果表明不同工况条件下,平均低水位以上的滩面均为净淤积,水下部分侵蚀明显,滩面上部泥沙不断堆积,砾石海滩最终形成稳定剖面。研究结果可为类似砾石海滩养护工程设计提供参考。     

蓬菜西庄海滩示踪砂试验研究

为了研究蓬菜西庄海岸侵蚀原因，揭示泥沙运移规律，利用萤光示踪砂和染色砾石进行侵蚀岸段的泥沙示踪研究。其主要结果如下：１．海滩泥沙运动完全由波浪控制，泥沙运移的速度和方向取决于破波的大小和方向。２．海滩泥以群体形式沿岸输移。３．在平直海岸上，泥沙可超越粘土质海蚀平台进入另一砂质海滩。     

蓬莱西庄海滩示踪砂试验研究

为了研究蓬莱西庄海岸侵蚀原因、揭示泥沙运移规律，利用萤光示踪砂和染色砾石进行侵蚀岸段的泥沙示踪研究．其主要结果如下：１．海滩泥沙运动完全由波浪控制，泥沙运移的速度和方向取决于破波的大小和方向．２．海滩泥沙以群体形式沿岸输移．３．在平直海岸上，泥沙可超越粘土质海蚀平台进入另一砂质海滩。     

海南万宁大花角巨砾石海滩特征与成因

巨砾石是颗粒直径大于256 mm的沉积物.巨砾石海滩(Boulder beach)是一种少见的海岸类型,形成条件特殊,与砾石海滩(2～60 mm)沉积动力特征不同,是具有旅游价值和学术价值的资源.对海南万宁大花角巨砾石海滩的调查研究结果表明,海滩主要是由直径500～1000mm、磨圆、光滑的巨砾石排列而成的,剖面平滑,宽40m,高9 m,海滩坡度13°.与普陀岛的巨砾海滩相比,本海滩更为典型,海滩巨砾石磨圆更好、宽度更大、海滩低潮至高潮之间高度更大,海滩形态也更完好.它的形成与海岸岬湾地形、地质条件、高能波浪等有关.巨砾石磨圆极好、表面光滑,但是粒径比一般鹅卵石大1～2个数量级.巨砾石海滩与砾石滩在沉积特征和动力地貌特征不同,是不同类型的海滩.     

秦皇岛地区侵蚀性海滩的演化及保护

秦皇岛地区的旅游海滩大部分处于侵蚀状态,沿海河流入海沙量的减少是引起海滩侵蚀的主要原因。对比不同时期的海岸剖面资料,论述了侵蚀性海滩滩面变窄、滩砂粗化和滩面变陡等问题。在讨论海岸侵蚀与海滩侵蚀两个概念的区别和内在联系基础上,依据海滩的岸坡物质对秦皇岛地区侵蚀性滩海进行了分类,侵蚀性海滩的保护及恢复的关键问题是海滩发育空间及物源,最后,针对不同类型的侵蚀海滩,提出了具体防护措施。     

人类工程活动对秦皇岛海滩侵蚀及淤积的影响

秦皇岛地区旅游性海滩的侵蚀主要是人类所实施的以水库为主的河流水利工程而产生的海岸效应。在区域性海滩普遍遭受侵蚀状态下，沿海港口工程又通过三种不同形式第滩发育施以影响，其一是对沿岸泥沙流的拦阻，其二为在局部岸段形成完全或不完全波影区，其三为人工岬湾的形成，港工引成的海滩淤积体特征是海滩变宽、变缓及海滩砂细化。文中最后讨论了侵蚀性海滩向演化的发育空间问题。     

浙江朱家尖岛东沙海滩对热带风暴“娜基莉”的响应及风暴后的恢复

海滩对风暴的响应及风暴后海滩的恢复过程一直以来都是国内外海滩研究的热点。本文通过对浙江舟山市朱家尖岛东沙海滩地形地貌的现场调查，对比分析了热带风暴"娜基莉"影响下东沙海滩剖面的蚀积变化，探讨了海滩在热带风暴发生后的恢复情况。结果表明，在"娜基莉"影响期间，因风暴浪为向岸浪，东沙海滩几乎遭受全线侵蚀，12个剖面单宽侵蚀总量为73.46 m3/m，其中海滩直线段较两个遮蔽段侵蚀显著。由于海滩在风暴前进方向的左侧，且"娜基莉"距东沙较远，使得东沙海滩普遍侵蚀但强度较小。东沙海滩在热带风暴后的恢复过程中，不同部位的地貌调整和冲淤变化不同，下岬角遮蔽段基本趋于稳定，直线段和上岬角遮蔽段在恢复过程中因受海滩季节性调整的影响呈现持续侵蚀。     

基于数字图像的山东长山岛砾石海滩表层砾石形貌特征研究

天然砾石海滩作为一种高能环境下的海岸堆积体,因其粒径粗、孔隙度大等特征,是良好的海岸防护屏障。了解砾石海滩形成过程离不开砾石形貌这一重要参数,但要快速、准确获得大量砾石的定量参数比较困难。本文对山东北长山岛3个砾石海滩(九丈崖、月牙湾、长滩)、南长山岛的4个砾石海滩(仙境源、林海、长山尾和明珠广场)进行现场剖面测量并采集砾石样品及砾石图像,应用ImageJ软件对砾石进行原位无干扰数字图像测算,可以快速大量分析砾石粒径、磨圆度等形貌参数。结果显示:砾石的粒径范围为4～79 mm,主要集中在中砾,各海滩分选较好;其中,北长山岛海滩的砾石平均粒径略小于南长山岛,北长山岛九丈崖海滩的砾石平均粒径最大,南长山岛的仙境源海滩砾石平均粒径最小。向海方向从滩肩到高潮线平均粒径逐渐减小,但在水边线处增大。砾石磨圆度介于0.59～0.75之间,等级均为圆状,砾石海滩均已达到较成熟阶段;其中北长山岛的月牙湾海滩砾石磨圆最好,长滩海滩砾石的磨圆最差,由陆向海磨圆度值呈增大的趋势。形状比率范围介于1.36～1.77之间,与磨圆度呈明显负相关(R2=0.98),砾石由陆向海从长条状渐变为椭圆状。南、北长山岛的砾石海滩的砾石形貌受到物源、动力条件和人为活动的影响。研究区砾石海滩坡度范围为16%～35%,海滩坡度与沉积物粒径呈正相关。     

海南岛东北部海滩侵蚀与恢复对连续台风的复杂响应

在连续台风作用下海滩的侵蚀与恢复是一个复杂的过程。基于海南岛东北部木兰-抱虎湾海滩的现场调查,对比分析台风"威马逊"和"海鸥"登陆前后海滩剖面和后滨沉积物的动态响应。结果表明,超强台风"威马逊"引起海滩的严重侵蚀和强烈的泥沙输移,在木兰湾海滩主要表现出由北向南沿岸海滩的差异性变化,在抱虎湾各海滩变化较为相近;后继登陆台风"海鸥"引起海滩显著堆积,对海滩主要起恢复作用,木兰湾海滩恢复效果明显,海滩后滨沉积物趋于恢复至台风前的状态,由于抱虎湾水下珊瑚礁及近岸岩礁地貌减缓了台风对该处海滩的侵蚀和堆积作用,抱虎湾海滩表现出与台风前较大差异性。两处海湾海滩的不同走向及台风的风向变化也是造成海滩不同响应的重要原因。研究将有助于更好地理解海滩对连续台风作用的复杂响应。     

Variations in grain‐size and sorting on two kaikoura beaches

Two exposed, high‐energy beaches on the Kaikoura coast of New Zealand are composed of sand and gravel derived from a greywacke terrain. Both beaches can be classified as mixed beaches although the sediment varies from dominantly gravel at the ends of the beach to dominantly sand at the centre, through transition zones in which sand and gravel are mixed. Sixty‐four surface samples were analysed for grain size; two sediment parameters, mean grain size (M_z) and sorting (σ_I), were calculated.

A striking feature of the cumulative frequency curves is that both unimodai and bimodal distributions include median sizes over the whole range of sampled material, even though bimodal samples display two strong modes in the sand and gravel grades. The general deficiency lof sediment dn the very coarse sand and granule classes (0 to — 2 _F ) noted by numerous authors in many parts of the world is apparent in the poorly‐sorted bimodal samples. However, the best‐sorted samples also occur in these two classes.

Mean grain size of samples ranges from medium sand (1.820) to medium pebbles (—4.7 _F ), and sorting ranges from very well sorted (0.250) to very poorly sorted (2.69 _F ). Mean erain size on the northern beach is significantly greater than on the southern beach, but values of sorting are comparable. The greater mean size on one beach compared with the other is thought to be a function of the grade of material supplied by local rivers; the similarity in sorting presumably reflects the similarity of the processes acting on the two beaches.

Mixed sand‐shingle beaches are relatively rare on a world scale but common in New Zealand. Sediment distributions along the Kaikoura beaches do not reveal a regular decrease in size away from the rivers which supply material to shore at present. Instead, the beaches are differentiated into a number of sediment zones composed of either sand, or mixed sand‐gravel, or gravel. On each beach a gravel zone is located furthest from the river outlets. Sorting generally improves toward the Kaikoura Peninsula. Explanations for these trends are not given. Variations in size and sorting across the two beaches do not show a well developed zonation because of the high level of wave energy which continually mixes the material across the beach.     

威海典型海滩沉积地貌及质量评价

选择威海双岛湾附近海滩、国际海水浴场海滩、金海滩、青叽岛以西海滩、青叽岛以东海滩、天鹅湖海滩、桑沟湾海滩、楮岛海滩、南海新区海滩和乳山银滩十处代表性岸滩进行了海滩地貌和底质调查,结合沙滩表层样品分析测试数据,对研究区海滩地貌、沉积物粒度分布特征及海滩质量进行了综合评价。结果表明:威海海滩沉积物主要包括砾砂、粗砂、中砂、细砂四种类型,其中中砂分布最广,约占所有点位的35.6%,细砂、粗砂、砾砂分别占34.4%,26.7%和3.3%。岸滩坡度一般较缓,宽度中等以上,岸滩质量整体较好,部分岸滩受沉积物粒度影响,质量稍差。     

Large scale experiments on gravel and mixed beaches: Experimental procedure,data documentation and initial results

This paper provides information on the experimental set-up, data collection methods and results to date for the project “Large scale modelling of coarse grained beaches”, undertaken at the Large Wave Channel (GWK) of FZK in Hannover by an international group of researchers in Spring 2002. The main objective of the experiments was to provide full scale measurements of cross-shore processes on gravel and mixed beaches for the verification and further development of cross-shore numerical models of gravel and mixed sediment beaches. Identical random and regular wave tests were undertaken for a gravel beach and a mixed sand/gravel beach set up in the flume. Measurements included profile development, water surface elevation along the flume, internal pressures in the swash zone, piezometric head levels within the beach, run-up, flow velocities in the surf-zone and sediment size distributions.The purpose of the paper is to present to the scientific community the experimental procedure, a summary of the data collected, some initial results, as well as a brief outline of the on-going research being carried out with the data by different research groups. The experimental data is available to all the scientific community following submission of a statement of objectives, specification of data requirements and an agreement to abide with the GWK and EU protocols.     

台风季节朱家尖岛砂、砾质岬湾海滩的不同沉积地貌动态变化

岬湾砂、砾质海岸是海岛、海岸带重要的旅游资源, 具有较高的社会经济和生态价值, 长期以来备受关注。本文以浙江朱家尖岛东岸的5个代表性岬湾海滩为例, 基于2019年台风季节早期、中期及晚期测量获得的海滩地形和沉积物数据, 结合海滩近岸的水动力数据, 分析了砂质海滩和砾石海滩这两种不同类型岬湾海滩的沉积地貌动态变化。结果表明, 朱家尖岛东岸5个海滩在台风季节出现了不同的体积变化, 大沙里、东沙、千沙、乌石塘和小乌石塘海滩的单宽体积变化分别为11.93m³·m^-1、-54.41m³·m^-1、-19.75m³·m^-1、2.19m³·m^-1和-1.96m³·m^-1。砾石滩较砂质海滩更为稳定, 无人类活动干扰的砂质海滩在台风季节侵蚀更少、变化更小。台风季节大沙里、东沙、千沙、乌石塘和小乌石塘海滩表层沉积物的平均粒径分别为2.47Փ、2.24Փ、2.64Փ、-5.96Փ和-6.03Փ, 粒径粗化和离岸输运是5个海滩表层沉积物在台风季节的主要表现, 砂质海滩的沉积物粒度特征变化比砾石海滩要大。沉积物粒径、台风强度及台风期间的主要波向与海滩走向之间的关系、海岸工程这3种因素都可能对海滩在台风季节的沉积地貌动态变化产生影响。本文研究结果可为台风季节的海滩管理提供参考。     

深圳龙岐湾海滩资源调查与开发建议

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。     

Longshore sorting on a beach under wave action

Sorting of sediment on a beach under wave action takes several forms. Stratified layers of finer and coarser sediment, which depend on wave climate, grain size and beach slope are formed. This complex problem can be simplified by defining the cross-shore and longshore sorting according to the angle between the breaking wave and the coast. In the present study, longshore distribution of sediment as well as corresponding beach profiles was measured in a wave basin. Three-dimensional hydraulic model experiments were performed with regular waves. Eighteen sets of experiments performed in longshore sorting mechanism using two different sand beds. The sorting of the bed material and the formation of armour coats along the beach were defined by grain size distributions and dimensionless parameters for sandy beaches.The rate of sediment transport with grain size sorting was measured in a wave basin. A method introduced sorting process was presented in this study. The sediment rate based on sorting mechanism was also discussed with known methods. It has been found that the non-uniformity of the grain size and hence sorting of the beaches play a very important role in the sand transport due to wave motion in a similar way to the case of steady flow in alluvial channels.     

Application of the parabolic bay shape equation to sand and gravel beaches on Mediterranean coasts

The equation most commonly used to describe the bay planform was proposed by Hsu and Evans (1989) and it was obtained through empirical analysis of sand beach planforms.In the last decade interest in gravel sediments increased owing to their greater stability on beaches, compared with sand sediments. Due to the differences between the morphodynamics of sand and gravel beaches, which is strictly influenced by their different hydraulic characteristics, it was necessary to create a predictive instrument for this beach type as well.Therefore, in this study the standard Hsu and Evans equation (1989) was modified in order to make it applicable not only to sand beaches but also to gravel beaches. The shoreline was computed according to a parabolic model in polar coordinates whose coefficients are considered linearly dependent on the wave direction and related to the beach type. The estimation of the free parameters of the model was performed according to a statistical analysis of a shorelines data set of Mediterranean sand and gravel embayed beaches.     

Stability of an artificially nourished beach,Balaena Bay,Wellington Harbour,New Zealand

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.     

日照海岸带沙滩侵蚀现状及沉积物粒度特征分析

通过对日照市海岸带2个重点沙滩的现场调查和沉积物粒度计算,综合分析了沙滩的侵蚀现状和粒度参数特征。海滨国家森林公园沙滩北部和南部处于侵蚀状态,中部为缓慢淤积状态;万平口海水浴场沙滩北部、中部总体呈侵蚀趋势,南部为淤积状态。海滨国家森林公园沙滩的平均粒径总体要小于万平口海水浴场沙滩,这与两沙滩的坡度不同有关,平均粒径从滩肩到低潮线逐渐变小。海滨国家森林公园沙滩的分选性要好于万平口海水浴场沙滩,分选系数具有由陆向海、由北向南逐渐变小的趋势。沙滩的滩肩和滩面处频率曲线主要为双峰,峰态平坦,物质来源复杂,低潮线处频率曲线主要为单峰,峰态尖锐,物质来源单一。