砾石海滩的沉积和形态动力特征

天然砾石海滩的物质主要来源于河流输入，海岸侵蚀，海底侵蚀，沿岸输送，人类活动及冰川搬运等，砾石海滩在地貌上表现出明显的分带性，海滩坡度的大小随物源和动力条件发生变化，砾石的磨蚀速率与岩性及周围沉积物粒度组成有关，人工砾石海滩建设可借鉴天然砾石海滩的形成和演化过程，合理地设计物质组成，砾石形状和大小，以便能更快地使人工海滩达到平衡状态并维持海滩的稳定性。

SEDIMENTODYNAMIC AND MORPHODYNAMIC CHARACTERISTICS OF GRAVEL BEACHES

Material sources for natural gravel beaches include river input, cliff recession, seabed erosion, longshore drift, glacier rafting and human activities. Geomorphologically, gravel beaches can be divided into several zones, which are caused by hydraulic material sorting. The shore face slope is a function of the sediment supply and hydrodynamic conditions. The gravel sediment is subjected to abrasive processes, the rate of which is controlled by the lithology of the material as well as the particle size distributions of the ambient sediments. The knowledge of the formation and evolution of these beaches is beneficial to the construction of artificial beaches that are used for coast protection and tourism purposes. It is important to determine in an appropriate way the composition of the materials for beach filling in terms of grain hardness, shape and size, so that the artificial beach will reach an equilibrium state and maintain its morphologic stability.