【作者】 王艳红；

【导师】 王建； 喻国华；

【作者基本信息】 南京师范大学 ， 自然地理学， 2006， 博士

【摘要】 历史时期江苏北部海岸淤进蚀退趋势性过程的逆转一直是海岸动力地貌研究的热点，就长周期的区域性海岸演变而言，公元1855年以来废黄河三角洲海岸侵蚀进程中局部变异现象同样值得关注。近150年来，由于黄河北归后陆源泥沙断绝，废黄河三角洲海岸一直处于强侵蚀状态，现有防护工程虽基本控制了岸线蚀退，但堤外岸滩和水下岸坡的侵蚀仍在继续。在此过程中海岸组成物质粗化、岸滩坡度陡化等现象反映海岸性质存在由淤泥质海岸向砂质海岸变异的趋势。然而以往关于海岸侵蚀的研究中尚无针对海岸变异的专门探讨，成熟的海岸防护措施多针对砂质海岸。本文以海岸变异为主线对废黄河三角洲海岸演变进行全面分析，旨在探索淤泥质海岸侵蚀进程中局部岸段发生变异的机理，为更加有效的海岸防护提供基础。具体开展了如下几方面的研究： ①就苏北海岸演变的历史资料和已有研究成果，论证了黄河尾闾变迁影响下的海岸演变过程中所伴随的海岸性质变异，即砂质海岸和淤泥质海岸之间的相互转换过程；②通过综合地貌调查、沉积物采样与分析、海岸动力泥沙环境分析、不同时期水下地形和断面资料对比、多时相遥感影像的岸线对比分析和不同潮时悬沙含量遥感反演等手段，从海岸侵蚀动态、侵蚀时空差异及泥沙运移等方面揭示海岸侵蚀过程中存在的变异现象及其进程；③通过废黄河口凹入岸段波浪泥沙物理模型试验，研究海岸性质变异中稳定岬湾的形成、粗颗粒泥沙来源、岬湾岸线形态等特征；并对比分析了变异形成的砂质海岸岸弧形态与典型砂质海岸稳定岸弧形态的异同；同时通过不同波浪条件下稳定岸弧形成的系列试验，探讨了变异型砂质海岸岸弧形态对波浪动力的响应；④根据废黄河三角洲海岸侵蚀变异特征、物质组成和动力泥沙环境的特殊性以及稳定岸弧形成过程的研究结果，论证了岬角控制在废黄河三角洲海岸整体防护中的适用性及构建整体防护体系的途径。 研究认为：①目前废黄河三角洲淤泥质海岸侵蚀进程中存在向砂质海岸变异的现象，其过程属历史时期海岸淤进进程中性质变异的逆向调整；②侵蚀动力的时空差异及泥沙运移特征是废黄河三角洲海岸侵蚀现状存在差异的主要原因。随侵蚀过程中波浪优势的增强和粗化泥沙的富集，海岸侵蚀中的变异在地貌上表现为向波控砂质海岸特征发展；③废黄河三角洲海岸侵蚀过程中存在的变异特征，使得通过岬角控制也能形成稳定岸弧，为海岸整体防护体系的构建提供了新的途径。更多还原

【Abstract】 The historical evolution tendency of North Jiangsu coastline is one of the hot spots on the field of coastal dynamic geomorphology in China. As far as a long-term regional coast evolution is considered, the appearance of local variance during the course of intensive erosion on the Abandoned Huanghe River Delta Coast since 1855 is equally noteworthy. In the past one and a half centuries, due to the absolute losing of sediment supply from the old Huanghe River, the Delta Coast was fearfully and continually eroded. Current coastline has been basically stopped from retreating by coast protection engineerings. Yet the beach and the submarine coast slope are still in eroding as before. Coastal changes during eroding, such as surface sediment coarsening and profile steepenning, indicate a tendentious change of coast nature from muddy to sandy is in vogue. However, a comprehensive discussion on coast nature variation is almost absent previously. And the existing protection engineerings are mostly aimed at sandy coast erosion. Take coast variation as a handhold, the paper worked over the erosion and the concomitant variation of the coast, to explore the mechanism of variation during erosion, so as to support effective measures for coastal protection, covered following aspects:①Based on historical recordations and approved research productions of the coast evolution in North Jiangsu, variation of coast nature during the course of eroding caused by the migration of the lower reach of the old Huanghe River was discussed, namely the transition processes between sandy and muddy coast;②Integrated field investigations, sediment sampling and analyses, coastal dynamic and sediment environment analyses, comparison among submarine landforms and coastal profiles of various time phases, comparison of coastlines from remote sensing images of various phases, calculation of suspended sediment concentration from remote sensing data, are employed to clarify the phenomenon and course of variation arisesed during coast eroding; ③ Based on a wave-sediment physical model of the concave seawall coast stretch on the Abandoned Huanghe River Mouth, formation process of the stable bay during the variation of coast nature, origin of coarsened sediments, characters of the bay shape and so on were studied. Similarities and differences between bay shapes of variational and typical sandy coast were also analyzed, and responses of bay shape to wave energy on variational sandy coast are discussed by serial experiments of different wave conditions as well; And ④, according to the features of coastal variation, particularity of sediments and dynamic environment and course of formation of a stable bay concluded from previous study, applicability of employing headland control on coastal protection, and approaches of constructing an integrated protection system on the Abandoned Huanghe River Delta Coast are demonstrated.Concluded: ①The Abandoned Huanghe River Delta muddy coast is varying to a sandy coast currently. The course belongs to a conversed regulation of nature variation during coast progradation in the historical period; ②Temporally and spatial diversities of dynamics and sediment transportation tendency is the mean cause of existing diversities of erosion. With the process of enhancing of wave dominance and enriching of coarsened sediment, the variation appearance tends to develop toward a wave dominated sandy coast on geomorphologic aspects; And ③, the existing variation of the Abandoned Huanghe River Delta Coast during eroding made it possible for headland control to form stable bays, and provided a fresh approach to construct an integrated protection system.更多还原