华南岬间砂质海岸稳定性研究

岬间海湾平衡平面形态规律在海岸长期侵蚀演变预测方面有着广泛的应用,已成为国外研究砂质海岸演变与稳定的重要课题。首先回顾了三种比较典型的经验岬湾形态方程,然后运用当前确定岬间海湾静态平衡形态最广泛使用的经验关系—抛物线关系,对华南31个岬间海湾的稳定状况进行了预测、分类。同时,采用数字岸线分析系统,计算了1990~2000年前后华南岬湾海滩的岸线进退速率,进一步分析、探讨了华南岬间海湾岸滩的稳定状况。     

舟山基湖海岸岸线形态与稳定性

抛物线模型是确定岬间海湾静态平面平衡形态中应用最广泛的关系式。应用此模型研究了舟山基湖砂质岸线的平面形态与稳定性,并通过近年来的海滩冲淤变化分析与沿岸输沙计算,对模型判定结果进行了对比验证。结果显示,基湖岸线已接近静态平衡,西北部略有淤进,中部稳定,东南部将有较大程度的淤进;模型判定结果与其他2种方法得出的结论相一致,印证了抛物线模型应用于此的合理性。     

海南万宁岬湾海岸海滩稳定性研究

岬湾海岸海滩的稳定性及其演变是砂质海岸研究的重要内容。基于多期遥感影像、海滩沉积物粒度分布,并采用岬湾海滩平衡形态模型(MEPBAY),分析探讨了海南岛东部万宁4个典型岬湾海岸海滩的稳定性及其模型的应用。研究表明,除东澳湾凸角处于不稳定状态,其余海岸处于静态或准静态平衡状态;岬湾海滩沉积物粒度在遮蔽段和开敞段有明显的差异,相邻海滩之间没有明显的泥沙交换,每个岬湾海滩都是相对独立的地貌单元;模型中上岬角控制点选取应考虑岛礁及水下礁坪;抛物线模型可以拓展应用于有离岸岛情况下的海湾。研究成果可为岬湾海滩的稳定性评估和管理提供科学依据。     

静态平衡岬湾海岸理论中抛物线方程在海滩养护中的应用

岬湾海岸是全球重要的海岸地形,约占全球岸线的51%。岬间海滩又是岬湾海岸地形中最重要的组成部分。20世纪40年代以来,海洋地质学家和海岸工程师们对岬湾海岸做了大量的研究。尤其在20世纪80年代,有关抛物线形状海湾方程的成果发表和后来相关计算机软件的开发,都对判断岬湾岸线稳定性和预测岬头下游海岸的静态平衡起到至关重要的作用。详细介绍了静态平衡岬湾的概念,并且通过在由动态平衡向静态平衡转化、以岸外坝群保护平直沙岸、提高单岬或丁坝下游的稳定性等方面的具体应用,验证了方程的有效性。通过适当的人工构筑物,配合人工养滩,创造静态平衡的海滩,对海岸带的开发和保护具有重要意义。     

岬间海湾平面平衡形态研究进展

岬间海湾平面平衡形态规律的研究是砂质海岸稳定与演变研究的重要内容。简要回顾了岬间海湾平面形态规律的研究进展,着重介绍了海湾平衡形态的五个模型。通过评述平衡形态模型的优缺点,指出机理分析和经验拟合相结合应该为以后海湾平面平衡形态规律的研究发展方向,并论述了我国岬间砂质海湾平面平衡形态研究的重要意义。     

岬间海湾平面平衡形态研究进展

岬间海湾平面平衡形态规律的研究是砂质海岸稳定与演变研究的重要内容.简要回顾了岬间海湾平面形态规律的研究进展,着重介绍了研究海湾平衡形态的五个模型.通过评述平衡形态模型的优缺点,指出机理分析和经验拟合相结合应该为以后海湾平面平衡形态规律的研究发展方向,并论述了我国岬间砂质海湾平面平衡形态研究的重要意义.     

岬湾海滩沉积动力地貌研究

岬湾海滩是砂质海岸稳定性及其演变的重要内容。介绍了岬间海湾平面形态平衡模型、海滩平衡剖面模式、海滩剖面主要类型的判别以及海岸泥沙运动,其中着重评述了现今岬间海湾平面形态平衡模型和海滩平衡剖面模式。通过它们的优缺点分析,认为人工神经网络模型是未来新型平面形态模型改进的方向;海滩平衡剖面模式分段使用,亦或2种或多种模式配合使用,更加符合实际情况。在以往研究中潮汐对海滩的影响往往被忽略,所以应加强对潮控海滩的研究;在泥沙输移方面至今还未有成熟系统的公式,现有的公式假定成分多,还有待进一步研究。提出了多学科综合集成是今后岬湾海滩研究的关键的思路。     

粤东靖海湾海岸地貌动力演变及其工程影响

受人为工程的影响,相对稳定的岬湾海岸地貌常经历显著的动态调整。本文以粤东靖海湾典型岬湾海岸为例,运用Mc Laren模型、波浪动力场数值模拟、等深线对比、冲淤计算等多种方法,从海岸地貌动力学角度,对人为岬角工程前后岬湾海岸地貌动力过程和冲淤演变进行综合分析。结果表明:1)海岸地貌动力系统内常存在负反馈机制以维持系统的稳定。岬角工程后上岬角防波堤沿SSW延伸,ESE和E向浪经过防波堤时发生绕射,波能削减,湾顶动力减弱,海滩沉积物从下岬角向湾顶反向运移;2)海滩的蚀积状态在工程前后发生了转换,工程前遮蔽段侵蚀、开敞段堆积;工程后遮蔽段堆积、开敞段侵蚀;3)海湾水下地形对岬角工程的响应敏感,工程后海湾水下地形冲淤剧烈。     

静态平衡岬湾海岸理论及其在黄、渤海海岸的应用

岬湾海岸是一种稳定的海岸存在形式,在天然海岸中岬湾地貌占51%。岬湾海岸研究是研究砂质海岸稳定性及演变的重要内容。岬湾海岸理论在海岸稳定性、海岸工程预测以及海岸综合治理方面有其重要的工程价值。文中详细讨论了岬湾理论中最具工程意义的抛物线型岬湾海岸线及基于静态平衡岬湾海岸理论开发的可视化应用软件MEPBay在海岸工程中的应用,并验证了该理论对黄、渤海海岸的适用性。MEPBay软件不仅有助于理解海岸形态过程,也是海岸工程师在岸线保护及海岸管理实践中的有力辅助工具。     

莱州湾东岸沿岸输沙率及冲淤演化动态分析

采用美国<海岸防护手册>的CERC公式对莱州湾东岸的沿岸输沙率进行计算;同时根据莱州湾东岸自身特征,采用岬间海湾平面平衡形态经验模型-抛物线模型对莱州湾东岸的平衡状态进行预测,结合两者分析得出莱州湾东岸的冲淤演化动态:屺姆岛南侧西端略有冲刷;龙口湾顶基本无泥沙进出;招远岸段遭受严重的侵蚀;石虎咀处于淤积状态.针对侵蚀岸段提出了防止海岸蚀退的对策.     

Numerical modeling of crenulate bay shapes

A numerical model is developed to compute the shoreline planform in a crenulate bay beach. The new model combines polar and Cartesian coordinates and can be used effectively to compute a hooked zone shoreline in the lee of upcoast headland. The model is calibrated using laboratory data with an incident wave angle ranging from 25° to 60°. The results of calibration and verification suggest that the ratio of the sediment transport parameters by wave and longshore current in this model is close to unity, and the computed shoreline planforms for the hooked and unhooked zones are in good agreement with the ones measured, especially when a bay is close to static equilibrium. In addition, the bay shape calculated by the present model is similar to that given by the well-known empirical parabolic equation for a bay in static equilibrium. The process of bay shape development from a straight beach to a static equilibrium bay is studied using laboratory experiments and the present numerical model. The temporal variations in the computed longshore sediment transport at different locations within a bay beach are analyzed. From this the decrease in the sediment transport becomes apparent while a bay beach changes its shape from straight toward a state of equilibrium. Based on this experience, it may be concluded that the present numerical model can produce a temporal change in the shoreline planform of a crenulate bay beach from a transition state to static equilibrium subject to seasonal wave action.     

人工岬角对龙口市月亮湾浴场的影响机制

岬湾海岸是世界上分布最为广泛的海岸形态,其形态特征可以反映岸线的长期冲淤变化趋势。龙口市月亮湾海水浴场于2005年建成之前,本是龙口沙坝——潟湖体系的沙坝沿岸部分,该平直岸线区域一直处于蚀退状态,蚀退速度为3 m/a。2个人工岬角在此建立之后,岬间海滩一直以1.5 m/a的速度缓慢淤积,目前已趋于平衡状态。笔者运用经验抛物线模型,通过Mepbay软件对海滩形态进行了模拟,初步确定了月亮湾海滩的平衡形态。2013年3月至2014年1月的定位剖面测量数据显示,月亮湾海滩单宽体积变化为17 m3/m左右。     

波浪谱形对不规则波数值模拟的影响

通过数值模拟分析了波浪谱形对不规则波浪数值模拟结果的影响.采用不同参数的JONSWAP谱模拟入射波要素,基于抛物型缓坡方程模拟不规则波浪的传播,分析了波浪谱形状对波浪数值模拟结果的影响.结果表明,采用抛物型缓坡方程模拟不规则波浪时,入射波浪谱形对模拟结果影响不明显;但由于模型中非线性项的影响,采用不规则波模拟的波高分布和采用规则波模拟的结果略有差别.     

Static bay beach concept for scientists and engineers: A review

Headland-bay beach (HBB) is one of the most prominent physiographic features on the oceanic margin of many countries in the world. Under the influence of a predominant swell, its curved periphery in natural environment may reach static equilibrium and remains stable without sediment supply from updrift and/or a riverain source within its own embayment. Coastal scientists and engineers have attempted to develop mathematical expressions to quantify this ideal bay shape since the 1940s. As the scenario with depleting sediment supply has become a common reality on many parts of the world coastline in more recent time, some coastal engineers have advocated a rational approach to mimicking the static bay shape found in nature in order to mitigate beach erosion as well as for coastal management. Nowadays, many useful applications have emerged since the publication of the parabolic bay shape equation (PBSE) developed for static equilibrium planform (SEP) in late 1980s. The advance in modern computer technologies and international collaboration has further facilitated the exchange of knowledge and applications of this static bay beach concept (SBBC).     

MEPBAY and SMC: Software tools to support different operational levels of headland-bay beach in coastal engineering projects

This paper presents MEPBAY and SMC software tools that allow comprehending and solving problems in headland-bay beach through a parabolic model. These tools can be employed as coastal engineering design tools (including nourishment designs) and also for academic purposes. They are oriented to different end-users, including coastal technicians, scientists and undergraduates and as coastal engineering design tools, they can be applied to different operational levels (pre-design and design). The aim of the paper is to present design guidelines, the capabilities of the tools, their potential use and applications. Both tools were applied to analyze San Lorenzo Beach and demonstrate their ability at different project levels.     

海岛岬湾海滩稳定性分析——以长岛明珠广场海滩和荣成镆铘岛海滩为例

海滩是海岛海岸重要的沉积地貌单元,其沉积特征和稳定性对于海滩的进一步开发利用和海滩养护具有重要意义。依据烟台长岛明珠广场海滩(人工沙滩)和威海荣成镆铘岛海滩剖面形态特征,结合表层沉积物粒度特征,分析了海滩剖面的稳定性,同时利用岬湾海滩静态平衡模型(MEPBAY),对两海滩平面形态的稳定性进行了分析和预测。结果表明：明珠广场海滩处于前滨严重侵蚀的不稳定态,镆铘岛海滩处于局部微侵蚀的轻度不稳定态。另外,从海岛海滩地理特征、水动力环境、泥沙来源和人类活动等方面简单归纳了两个海滩的侵蚀原因。     

Improved parabolic water wave transformation model

An improved parabolic water wave transformation model is developed based on generalized [1/1] Padé approximation. For forward scattered waves, the parabolic equation is solved using a marching scheme. The values of wave angles are calculated after the solution of each line; so that better [1/1] generalized Padé approximation is performed. The nonlinear effects are included using a modified dispersion equation. The model is easy to use and performs very well for complex bathymetry. The model is tested for cases of wave angles up to 70°. The numerical results show that for large wave angles, the new parabolic model is better than all the existing parabolic models based on rational approximation.