曹妃甸老龙沟潮汐通道口门深槽变迁的动力机制研究

The research results prove that in th Caofeidian sea area, the deep channels of the Laolonggou tidal inlet have had complex evolution trends from the developing to the shrinking since 1950s. The hydrodynamic mechanism for this phenomenon isn't still be explained, which is the key issue to be solved urgently concerning the study on the morphodynamic processes of the Laolonggou tidal inlet and the development of the Caofeidan Harbor. Based on the 2D wave-current sediment mathematical model covering the whole Bohai Bay and 3D turbulent-flow sediment mathematical model covering the Laolonggou tidal inlet, the effects on the hydrodynamic and sediment process are analyzed caused by the influencing factors such as the coastline migration and changes of sediment flux into the Bohai Bay, and the interaction, between the seabed evolution of the Laolonggou tidal inlet and the changes of the hydrodynamic and sediment conditions in the Bohai Bay, is discussed in detail. Accotding the above results, the main influencing factors resulted in the deep channel migration of the tidal inlet are anylyzed, and its hydrodynamic mechanism is obtained, and the understanding of the morphodynamic processes of the Laolonggou tidal inlet is improved. The effects on the deep channel evolution of Laolonggou outlet caused by the large-scale development of the Bohai Bay are predicted and the long-term evolution trend of the Laolonggou tidal inlet is presented, which povide the important scientific basis for the development and protection of the Bohai Bay, espeically the Caofeidian sea area.

长期地形资料对比发现，曹妃甸老龙沟潮汐通道口门的多个深槽存在从形成发展到趋于消亡的复杂迁移变化趋势，这种趋势性过程的原因和驱动力成为老龙沟潮汐通道系统冲淤动态研究和曹妃甸海区开发过程中亟待解决的问题。本研究拟从影响渤海湾水沙动力环境变化的主要因素－海岸淤蚀变迁、河口入海泥沙通量等入手，采用渤海湾大范围二维波流泥沙数学模型和老龙沟局部三维紊流泥沙数学模型相结合的方法，研究海岸变迁、入海泥沙通量变化等因素对渤海湾水沙动力过程的影响，以及改变后的水沙动力环境对潮汐通道地形地貌的重新塑造作用；分析导致潮汐通道口门深槽迁移变化的主导因素，明确主导动力机制，深化潮汐通道动力地貌过程的认识；进而研究渤海湾大规模开发对老龙沟口门深槽演变的影响，预测潮汐通道系统长周期的动力地貌演变趋势，为渤海湾沿海的开发利用与保护，特别是曹妃甸海区综合开发建设的决策活动提供科学依据。

作为一种特殊的海岸动力地貌类型，潮汐通道系统是研究海岸演变、水沙输移、海陆物质能量交换以及人类活动影响等方面的重要场所。本研究收集整理了渤海湾地区的水文地形和遥感影像等资料，分析了渤海湾的水沙运动特征与动力沉积环境，探讨了近百年来的海岸线变迁和滩槽演变规律；建立了波浪和潮流共同作用下的二维泥沙数学模型，研究了大规模高强度人类开发活动对渤海湾动力地貌演变过程的影响。深入研究了曹妃甸老龙沟潮汐通道系统动力地貌特征与滩槽冲淤演变规律，模拟分析了老龙沟潮汐通道口门深槽迁移变化的主导因素，阐明了潮汐通道深槽的动力形成机制，深化了对潮汐通道动力地貌过程的认识。建立了三维紊流泥沙数学模型，模拟分析了曹妃甸港区开发、唐山滨海新城采沙、东坑坨旅游岛开发等人类开发活动对老龙沟潮汐通道动力地貌演变的影响，预测了老龙沟潮汐通道系统的动力地貌演变趋势，为渤海湾沿海的开发利用与保护，特别是曹妃甸综合开发建设的决策活动提供科学依据。