东海岛海岸侵蚀研究

发布时间：2018-06-23 20:50

本文选题：东海岛 + 湛江湾　；参考：《国家海洋局第一海洋研究所》2015年硕士论文

【摘要】：东海岛位于广东省南部,是湛江市经济技术开发区的重要组成部分,是进出湛江港的门户,战略地位十分重要。做好东海岛岸线防灾减灾工作,保护天然沙滩资源,对于打造国家级循环经济试验区具有重要意义。同时,通过岸滩的地貌响应,分析湛江湾口门海洋动力情况及泥沙的输运特征,为研究湛江港深水航道的冲淤变化趋势提供科学支撑。本文依托海洋公益性行业科研专项“我国典型海岛地质灾害监测及预警示范研究”项目,通过实地调查、高分辨率卫星影像解译,对东海岛总体岸线侵蚀情况进行了分析。其中崩塘段砂质岸线侵蚀变化特征明显,加之紧邻湛江湾口门处,研究意义重大,对该处岸段进行重点监测与研究。通过高精度遥感卫片、无人机低空遥感监测数据、三维激光扫描数据、海滩剖面监测数据、沉积物粒度数据的处理与分析,结合前人研究成果,得出以下结论:(1)东海岛砂质岸线主要分布于海岛的西南侧、东南侧、崩塘三处。其中西南侧砂质岸线前期强烈侵蚀,之后进行了护岸工程建设,岸线趋于稳定;东南侧一直处于淤积状态,淤积速率最高达8.3m/yr;崩塘砂质岸线先淤积后轻微侵蚀,侵蚀速率为0.38m/yr。(2)崩塘段岸线在一年半的时间内发生较明显变化,整段岸线后退前移均有,以后退为主;灯塔附近200m岸线后退最为明显,平均后退距离约10m左右,最大后退距离达到17m。(3)崩塘段海滩整体以淤积为主,部分处于下蚀状态。其中最南侧海滩受虾池排污通道的影响,常年处于下蚀状态;灯塔附近滩面受灯塔影响明显,滩面最窄,且短时间内滩面发生过大幅度侵淤变化。(4)沉积物粒度变化与滩面冲淤特征较为一致。由于该处岸线系风成沙丘后退形成,沙丘砂较海底供砂细,海滩下蚀,沉积物变细;海滩淤积,沉积物变粗。(5)结合岸线与滩面变化特征,根据前人海滩灾害灾变强度分级方案,对海滩进行合理评价。该区大部分岸线处于稳定或轻微淤积状态,仅最南侧和灯塔附近岸线处于强侵蚀状态。(6)崩塘段海岸变化由多种因素造成的,总体受自然因素控制,人为因素对局部海岸的侵蚀影响明显。其中,海平面上升是长时间尺度因素,短时间内影响较小;风暴潮侵蚀能力强,短时间内可造成岸线大幅后退,是岸线侵蚀的主要自然因素;波浪、潮流是海底供砂的主要动力,是海滩砂的重要补给;人为因素对海滩的影响明显,虾池排污即可直接冲蚀滩面,又可阻断沿岸流供砂,对海滩的破坏作用最为严重;人工构筑物通过改变周围流场,引起海滩的冲淤变化;湛江湾内围填海活动降低湛江湾的纳潮量,影响泥沙向外输出。
[Abstract]:East Island is located in the south of Guangdong Province. It is an important part of Zhanjiang Economic and technological Development Zone and a gateway to Zhanjiang Port. The strategic position is very important. It is of great significance to do a good job of disaster prevention and mitigation along the coast of the East Island and to protect the natural beach resources for the establishment of a national experimental area of circular economy. At the same time, the characteristics of marine dynamics and sediment transport at the mouth of Zhanjiang Bay are analyzed through the landform response of the shoreline, which provides scientific support for the study of the trend of erosion and siltation in the deep-water channel of Zhanjiang Port. Based on the scientific research project of "Monitoring and early warning of Geological hazards in typical Islands of China", this paper analyzes the overall shoreline erosion of the East Sea Island through field investigation and interpretation of high resolution satellite images. The characteristics of erosion of sandy shoreline in bendang section are obvious, in addition, it is of great significance to study adjacent to the mouth of Zhanjiang Bay, so it is important to monitor and study the shoreline. Through the processing and analysis of high precision remote sensing satellite, UAV low altitude remote sensing monitoring data, 3D laser scanning data, beach profile monitoring data and sediment granularity data, combined with previous research results, The main conclusions are as follows: (1) the sandy shoreline of Donghai Island is mainly located in the southwest side, southeast side and collapse pond of the island. The southwest side of sandy shoreline was strongly eroded in the early stage, and then a revetment project was carried out. The shoreline tended to stabilize; the southeastern side was in a silting state, and the deposition rate was up to 8.3 m / yr; the sandy shoreline of the caving pond was silted first and then slightly eroded. The erosion rate is 0.38 m / yr. (2) the shoreline of the cauldron section changes obviously in one and a half years, and the receding front of the whole section is mainly backward, and the receding distance of 200 m shoreline near the lighthouse is the most obvious, and the average receding distance is about 10 m. The maximum receding distance is up to 17m. (3) the beach in the caving section is mainly silted and partly in the state of downward erosion. The southernmost beach is affected by the shrimp pond sewerage and is in the state of annual erosion. The beach surface near the lighthouse is obviously affected by the lighthouse, and the beach surface is the narrowest. The sediment size change is consistent with the erosion and deposition characteristics of the beach surface in a short period of time. (4) the grain size change of the sediment is consistent with the erosion and deposition characteristics of the beach surface in a short period of time. Because of the receding formation of wind-formed dunes along the shoreline system, sand dunes are thinner than those of the bottom of the sea, the beach is eroded, the sediments become thinner, the beach silts up, and the sediments become thicker. (5) combining the characteristics of shoreline and beach surface variation, according to the previous classification scheme of beach disaster intensity, Make a reasonable evaluation of the beach. Most of the shorelines in this area are stable or slightly deposited, and only the southernmost coast lines and near lighthouses are strongly eroded. (6) the coastal changes in the caving section are caused by many factors and are generally controlled by natural factors. The effect of human factors on local coastal erosion is obvious. Among them, sea level rise is a long time scale factor with little influence in a short time; storm surge has strong erosive ability and can cause shore line to recede in a short period of time, which is the main natural factor of shoreline erosion; wave, The tidal current is the main power of sand supply and the important recharge of beach sand, the influence of human factors on beach is obvious, the shrimp pond sewage can directly erode the beach surface, but also can block the coastal flow to supply sand, the damage to the beach is the most serious. Artificial structures change the surrounding flow field and cause erosion and siltation of the beaches, while the reclamations in Zhanjiang Bay reduce the tidal capacity of Zhanjiang Bay and affect the outward output of sediment.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P748

【参考文献】