共查询到19条相似文献，搜索用时 93 毫秒
1.
辽东湾两侧砂质海岸侵蚀灾害与防治 总被引：9，自引：1，他引：9
自20世纪60年代至90年代，由于多种原因，辽东湾东西两侧的初始沙质海岸侵蚀范围逐年扩大，侵蚀不断加剧，给当人民的生产和生活带来严重危害。由多年监测资料发现，侵蚀严重的熊岳岸线以2～4m／a的速率而大幅度后退，特别严重的地区最大后退达10km；辽西绥中某些岸段平均每年后退1～2m。20世纪90年代后期，由于一些海域管理措施的出台和相应的海岸防护工程的建设，海岸侵蚀逐渐减弱。通过现场调查和多年监测，分析了辽东湾东西两侧砂质海岸侵蚀的特点，认为海岸组成物质松散与海岸动力作用强烈是本区现代海岸侵蚀的基本条件，人为活动是关键因素，并提出了海岸侵蚀灾害的防治对策。 相似文献
2.
废黄河口海岸侵蚀与对策 总被引：9，自引：0，他引：9
废黄河三角洲海岸剖面形态以上凹形为特征,在平均大潮高潮位附近发育了小规模的贝壳堤或贝壳滩,中潮位有薄层蚀余物质堆积,其余大部分滩面均出露老的三角洲沉积。这说明废黄河口海岸侵蚀的主要动力是波浪作用,而平行于海岸的潮流则更加剧了侵蚀。在发育阶段上,废黄河口海岸侵蚀仍处于前期阶段,离开自然稳定状态还很远。按照顺应自然的原则,根据淤泥质海岸剖面的发育规律,本文提出了以海堤前人工填砂进行废黄河口海岸防护的方案。与海堤前抛石筑丁坝的方案相比,人工填砂方案技术较合理,投资较省。人工填砂的关键是待填物质粒径和填砂后海滩坡度的设计。 相似文献
3.
泉州市砂质海岸侵蚀特征及原因分析 总被引：2，自引：1，他引：1
基于泉州市沿岸岸滩侵蚀状况调查,结合海岸动力地貌学知识研究,分析泉州市沿岸岸滩侵蚀状况.调查岸段有32个,对其进行采样拍照及侵蚀现状描述,对7个岸段进行了剖面调查及沉积物分析.研究表明泉州市沙质海岸以岬控岸和沙坝--泻湖为主,岬控岸的沉积物和剖面表现为中细粒沉积和岸坡由近岸向海变平缓,而沙坝--泻湖岸则以粗粒沉积和岸坡起伏不平为特征,沉积物特征、沿岸输沙、平衡剖面及动力地貌均反映了泉州砂质海岸的侵蚀状况.在全球海平面上升的大背景下,除特大自然灾害影响,泉州近海域的人为活动恶化了海岸侵蚀的程度,其中以海砂开采最为严重. 相似文献
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厦门海岸侵蚀与防护对策 总被引：5，自引：6，他引：5
本文根据实地考察、调访、岸滩剖面重复水准测量和水文气象等资料的综合分析,对厦门岸滩侵蚀原因、危害及防护等问题进行了探讨研究。结果表明,基岩侵蚀岸平均侵蚀速率为6mm/a、红土台地岸为1～3m/a、砂质岸为1m/a。厦门岛东部海岸侵蚀最为严重。海岸侵蚀毁坏海岸工程和军事设施,吞没娱乐砂滩和土地,造成房屋崩塌。沙源严重亏失是造成海岸侵蚀的最主要原因;在岸滩上建造不合理的工程也加剧了海岸的侵蚀;强劲的东北波浪和台风激浪则是岸滩侵蚀的主要动力。本文对厦门岸滩侵蚀的防护问题,提出了六点建议。 相似文献
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漠阳江入海口东侧海岸侵蚀现状及成因分析 总被引：1，自引：0，他引：1
对漠阳江入海口东侧海岸的侵蚀情况进行了详细的野外调查,在2年的调查时间内对监测岸段的海岸线位置及海滩地形开展了5次重复测量。各次测量结果的对比表明,漠阳江入海口东侧海岸遭受了严重的侵蚀,岸线平均后退速率达15m.a 1;海滩地形剖面的动态变化则显示海岸侵蚀和淤积情况随季节而改变,在2008年台风"黑格比"登陆后,研究区岸线大幅后退,岸滩地形发生了深刻变化。通过对研究区海岸侵蚀特点的分析,认为砂质海岸的脆弱性和水动力作用是该区海岸侵蚀的基本条件,风暴潮是造成该区海岸严重侵蚀的重要因素;另外,人类活动也加剧了研究区的海岸侵蚀。 相似文献
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江苏吕四海岸沉积动力特征及侵蚀过程 总被引：1，自引：0，他引：1
海岸侵蚀与水动力之间有着密切的关系.基于现场调查和资料收集,探讨了吕四海岸地貌、水动力、泥沙运动以及沉积与动力之间的响应.研究结果表明,风浪和潮流是塑造吕四海岸的主要动力.风浪年内变化按向岸风频率可分为高频期(10 月至翌年 1月)、转频期(2 月、3 月和 9 月)和低频期(4～8月)三个时期.风浪高频期,潮滩冲蚀,物质粗化;低频期,潮滩淤积,物质细化;转频期,时冲时淤,动态稳定.潮流作用主要表现为输沙淤滩和侧蚀滩脚.在风浪高频期,滩脚同时受到风浪冲蚀和潮流侧蚀,向岸后退,使吕四岸段成为隐性侵蚀型海岸.岸滩塑造对沉积动力响应显著,东部处于滨岸环境,在潮流和风浪的作用下,沉积物由岸向海变粗;西部还受径流影响,处于滨岸-河口环境,物质由岸向海变细.在水动力要素中,风浪是导致岸滩侵蚀的主控动力,而潮流则是近岸泥沙进行滩槽滩槽交换和循环输运的输运动力. 相似文献
8.
针对海口市海岸侵蚀较为严重和特殊的政治、经济地位、从自然条件角度客以分析了诱发该地区海岸侵蚀的主要原因，分析了当前在海岸治理过程中遇到的现实问题，提出治理海口市侵蚀岸段的基本思路和主要措施，为政府决策部门提供依据。 相似文献
9.
浙江海岸侵蚀现象普遍存在。基岩海岸海蚀地貌发育,因其组成物质抗冲蚀能力强,岸线后退不明显;砂砾质海岸普遍发生侵蚀,尤其是无计划的人工挖沙,造成沙滩减小或消失;淤泥质海岸大多处于缓慢的淤涨状态,但由于自然条件的改变和人为作用的影响,某些岸段发生侵蚀,特别是受到台风暴潮的影响,岸线在短时间内出现大规模后退和滩面下蚀。侵蚀岸段主要见于杭州湾北岸澉浦至金丝娘桥岸段,杭州湾南岸临山至西三岸段及瓯江口北岸盘石至黄华岸段。淤泥质海岸后缘为滨海平原,组成物质为粘土质粉砂,抗冲蚀能力弱,为防止和减轻海岸侵蚀,沿岸建造各类海岸工程(海塘、丁坝、导堤等),提高防潮抗浪能力,在朝滩种植大米草,互花米草,消浪促淤明显。另外,在海岸开发活动中,应加强海岸侵蚀监测和综合管理。 相似文献
10.
琼州海峡南岸海岸动力地貌研究 总被引：6，自引：0，他引：6
岬湾相间的琼州海峡南岸在海岸动力条件作用下,岸滩发生侵蚀或堆积,特别是南岸中部的南渡江三角洲沿岸岸滩演变剧烈。该文从海岸动力地貌的角度,对琼州海峡南岸的海岸动力特征、泥沙运动以及岸滩演变进行分析。根据海峡南部三维潮流场数值模拟结果,结合经验公式初步分析潮流引起的泥沙运移速率和方向,得到岸外水域总的泥沙运移趋势为从西向东。根据波浪动力计算分析沿岸泥沙运移,探讨沙质岸滩的地貌演变之间的关系,得出海峡南 相似文献
11.
Li Yan-ting Zeng Cheng-jie Yi-han Zhao Hu Po Sun Tian-ting Hou Yi-jun Mo Dong-xue Wang Deng-ting 《中国海洋工程》2022,36(3):413-426
Storm surges are cataclysmic natural disasters that occur along the coasts and are usually accompanied by large waves. The effects of coupled storm surges and waves can pose a significant threat to coastal security. Previous laboratory studies on the effects of storm surges and waves on coastal structures have typically utilized steady water levels and constant wave elements. An indoor simulation of the coupled processes of tides and waves is developed by adding a tide generation system to an existing laboratory wave basin to model continuous dynamic tide levels so that tide generation and wave-making occur synchronously in the pool. Specific experimental methods are given, which are applied to further study waves overtopping on artificial sea dikes and coastal flooding evolution under the coupled actions of tides and waves. The results of the overtopping discharge obtained by the test with a dynamic water level are compared with those obtained from steady water level tests and the existing empirical formula. In addition, the impacts of ecological coastal shelterbelts and structures on coastal flood processes and distributions are also investigated. The proposed simulation methods provide a new approach for studying the effects of storm surges and waves on coastal areas. The study also aims to provide a reference for coastal protective engineering.
相似文献12.
Five generalized physical models of drfferent distortion ratios were bruit according to DOU Guo-ren‘s similarity theory of total sediment transport modeling for estuarine and coastal regions. Experiments on local scour in front of groins were made under the actions of tidal currents and waves with clear and sediment entraining water. The scour depths under different dynamic actions are compared. The effect of the distortion ratio on the depth of scour hole is discussed. A relationship between scour depths for distorted and undistorted models is given. 相似文献
13.
《Ocean & Coastal Management》2000,43(10-11):879-904
The article describes an on-going struggle between local planning authorities, regional fishery authorities and environmental authorities over the management of the Norwegian coastal zone. Particular reference is made to a recent planning project in Nordland County where 18 peripheral communes with weak planning traditions joined forces to produce structure plans for their coastal areas. Concepts of rationality and power are used as points of departure for an interpretation of the actions of the parties involved. The discursively rational nature of the planning project, embodying principles of consensus building, social integration and personal growth, is contrasted to the strictly instrumental behaviour of regional fishery and environmental authorities. The article also relates conflicts between communes and regional sector authorities to the power structure of the field of coastal management and the habitus of the different institutional actors. The actions of the fishery authorities are seen as a defence of their monopoly of the production of ideology in marine management, while the actions of the communes are interpreted as a bid by the periphery for greater control over local resources. 相似文献
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我国沿海地区是极端天气和气候事件易发频发区,也是重要的人口和经济聚集地。在全球气候变化背景下,风暴潮、海浪、海冰和海啸等海洋动力灾害的形成机理、发生规律、时空特征、损失程度呈现出新的特点,重特大海洋动力灾害对我国沿海地区造成的威胁不容忽视。文章阐述海洋动力灾害时空分布特征,在分析我国沿海地区应对海洋动力灾害现状基础上,提出我国沿海地区应对重特大海洋动力灾害的对策与建议:建议开展重特大海洋动力灾害防御相关立法研究,制订国家层面应对重特大海洋动力灾害专项应急预案,建立健全重特大海洋动力灾害保险风险补偿机制以及提升重特大海洋动力灾害科技支撑能力。 相似文献
15.
Bang-Fuh Chen 《Ocean Engineering》1999,26(1):47
A finite-differnece method was used to calculate the nonlinear hydrodynamic pressures acting on the coastal embankment faces by seismic-wave actions. The nonlinearity of free surface flow, convective acceleration, viscosity and surface tension of fluid are included in the analysis. The kinematic and dynamic free surface boundary conditions are employed for calculating the horizontal fluid velocity, pressure at the free surface and the surface profile of the fluid. The time-dependent water surface is transformed to the horizontal plane, and the flow field is mapped onto a rectangular, making it convenient to model the complex sea bottom geometry and the wavy water surface by the finite-difference method. Fully nonlinear and weakly nonlinear dynamic free surface conditions are used and compared. The effects of surface tension of fluid are also discussed. The nonslip boundary condition is applied on the most part of the interface between fluid and solid face, except the region near the intersection between free surface and wall face. The numerical results are presented for various water depths and ground motion intensities, and their associate viscous effects on coastal embankment hydrodynamics are discussed. 相似文献
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Filipe Rafael Ceia Joana Patrício João Carlos Marques João Alveirinho Dias 《Ocean & Coastal Management》2010,53(8):478-486
Coastal vulnerability in barrier island systems is extremely high. The barrier island shoreline is exposed to many threats, such as storm erosion, reductions in sediment longshore drift and sea level rise. Many of these threats to coastal areas, such as Ria Formosa, are likely to increase in the near future. The main objectives of the present study are to identify the areas in the system that are at most risk by assessing the evolution of the Ria Formosa barrier island system since the 1940s, and determine which interventions would be necessary to protect these areas.The coastal vulnerability of the system was assessed based on current literature, data available from official institutions, and aerial and terrestrial in situ examination. The results obtained for the evolution of the Ria Formosa coastal system reveal that there are several vulnerable areas that have very dynamic processes, such as extremely high evolution rates of islands and inlets. Human actions that affect the whole system, namely the construction of many physical structures, are the main cause of the instability. Moreover, as several stakeholders are involved, efficient management of the coastal system is imperative. Extensive and careful interventions are urgently needed to avoid irreversible negative impacts on the barrier island system. Three types of techniques could be adopted to deal with the threats to barrier islands: hard stabilization, soft techniques, and non-structural alternatives. However, using hard techniques has many negative effects compared to soft techniques, and as a result it is necessary to remove existing structures from the areas at most risk. 相似文献
18.
岬湾相间的琼州海峡南岸在海岸动力条件作用下,岸滩发生侵蚀或堆积,特别是南岸中部的南渡江三角洲沿岸岸滩演变剧烈。该文从海岸动力地貌的角度,对琼州海峡南岸的海岸动力特征、泥沙运动以及岸滩演变进行分析。根据海峡南部三维潮流场数值模拟结果,结合经验公式初步分析潮流引起的泥沙运移速率和方向,得到岸外水域总的泥沙运移趋势为从西向东。根据波浪动力计算分析沿岸泥沙运移,探讨沙质岸滩的动态与地貌演变之间的关系,得出海峡南岸海岸地貌演变与盛行的NE和NNE向风浪有密切关系,岸滩的演变过程主要受制于这两个方向的风浪及其引起的泥沙沿岸运移。 相似文献
19.
波浪和潮汐作用下的海滩剖面动态变化过程是海岸演变及沿海防护工程设计与旅游资源规划的核心内容。本文以广西钦州湾沙井半岛人工海滩为研究区, 基于GPS-RTK采集的2018年1月—2019年12月的逐月剖面高程实测数据, 通过分析剖面冲淤和单宽体积变化, 利用EOF(Empirical Orthogonal Function)函数揭示剖面的高程变化模式, 进而探讨海滩剖面的动态演变过程。研究的主要结果表明: 1) 在观测期间, 人工海滩剖面的冲淤情况整体展现出冬春季淤积、夏秋季侵蚀的变化特征; 2) 人工海滩剖面因泥沙横向输移而导致不同横向分带的单宽体积变化趋势呈差异性, 不同横向分带具有侵蚀与淤积交替出现的情况; 3) 人工海滩剖面的变化模式可划分为由强降雨及台风导致剖面高程明显降低的主要模式、波潮影响下的剖面高程经历强降雨及台风后逐渐淤积和恢复的次要模式、波浪破碎形成卷流引起滩面冲淤变化的其他模式。 相似文献