Evaluation of the characteristics of sediment in coastal shallow sea area and development of the prediction method for maddiness environment

来自河流的细颗粒沉积在海湾的内部，形成了一个巨大的潮滩。在海洋工程建设中，河口的悬浮物和泥沙颗粒带来了一些环境问题。需要建立估算浆液粘土沉降和泥质在海水中的扩散的方法。本文对沉积物的一些特性和悬浮泥浆颗粒的运移进行了研究。研究了潮滩表层沉积物的物理化学和力学性质以及底栖生物的分布。结果表明，地表沉积物在整个深度上呈现恒定的粘土矿物组成，从沉积物的抗剪强度和固结特性来看，地表沉积物呈现超固结状态。在伊马祖河口地区，粘土与泥中有机质含量呈显著正相关关系，在- 150mv氧化还原电位附近，单位面积上的有机质含量最大。提出了一种确定浆液粘土沉降岩土参数的方法，并用考虑环内摩擦力的固结方程解释了固结时间与固结量的关系。基于环形水槽实验和现场观测的伊莎哈亚湾的潮流速度和悬浮泥浆颗粒浓度，用泥沙抗剪强度与沉积物表层屈服应力的相对相关性来表示浊度的发生。明渠试验发现，泥沙颗粒的湍流扩散系数和沉降速度与流速波动的功率谱形状有关。在此基础上，开发了估算近海混浊度的代码，并对有明海进行了数值模拟，成功编写了数值模型。少

Fine particles transported from rivers are deposited in an inner part of the bay, forming a vast tidal flat. The suspended materials and mud particles in estuaries bring about some environmental problems during the construction work in the sea. Establishment of the methods is needed to estimate the settlement of slurry clay and diffusion of muddiness in sea water. In the present work, some characteristics of the sediments and the transportation of the suspended mud particles have been studied.The physico-chemical and mechanical properties of the surface sediment and the distribution of benthos in a tidal flat have been investigated. The results showed that the surface sediment exhibits constant clay mineral composition throughout depth, and overconsolidated state in view of the shear strength and consolidation characteristics of the sediment. It was also indicated for Imazu estuary area that a positive correlation exists between clay and organic contents in the mud, and the weight of c … More apitata per unit area was the maximum at around-150mV redox potential. A method was proposed to determine the geotechnical parameters for the settlement of slurry clay, and the relationship of the time and the amount of consolidation was explained by the consolidation equation which took into account the friction inside of the ring.The occurrence of turbidity was formulated in terms of the relative correlation of the shear strength of mud against the yield stress of the sediment surface zone, based on the annular flume experiments and the on-site observation of tidal current velocity and the concentration of suspended mud particles in Isahaya Bay. Turbulent diffusion coefficient and settling velocity of the suspended mud particles were found, from the open channel experiments, to be dependent on the shape of power spectrum of the velocity fluctuation.Based on the results thus obtained, the code to estimate the muddiness in coastal sea has been developed and numerical simulations were conducted for Ariake Sea, and the numerical model was successfully coded. Less