Study of Oceanic Wave and Submarine Mass Movement

本项目的目的是弄清海底土层与波浪，特别是风暴波相互作用所引起的海底土层液化、土体移动和砂体运移的现象和过程。1）对相模湾、骏河湾和濑户内海海底土壤剖面特征的研究表明，采用颗粒简化公式可以很好地描述沉积物剖面。利用这些方程，可以根据含水量、孔隙比、不排水抗剪强度、无侧限抗压强度和有效超载压力预测沉积物剖面。2）地质和历史时期由风暴波引起的块状运动沉积物是细粒到极细粒的分选良好的砂，不包括大于粉砂尺寸的较小颗粒。它们显示出典型的丘状分层。席状沙地被暴风雨冲刷 ...更多信息 3）推导了波浪条件与土层液化发生的一般关系。通过试验研究发现，孔隙水压力系数对液化的影响大于固结效率对液化的影响。4）为了研究粘土夹层中的液化和流砂，进行了振动沉管模型试验。结果表明，在液化阶段，土体存在振动动水压力，这表明土体在液化过程中发生了动态流动，粘性土层的阻力加速了液化过程。5）利用Fokker-Planck方程，从概率的角度研究了波浪和浊流共存条件下砂土的运动。结果表明，运输距离服从高斯分布，运输距离随时间增加而增加。少

The purpose of this project is to make clear the phenomena and the process of liquefaction and mass-movement of submarine soil layers, and of the transportation of sand body, which are caused by the interaction between submarine soil layer and wave, especially storm wave. The results are summarized as follows :1) The investigation of characteristics of the submarine soil profile in Sagami Bay, Suruga Bay and Seto Inner Sea reveals that sediment profiles can be well expressed by the simplified equations deduced assuming grains. Using the equations, sediment profiles can be predicted in terms of water content, void ration, undrained shear strength, unconfined compressive strength and effective overburdened pressure.2) The mass-movement sediments caused by storm waves in the geologic and historical ages are fine- to very fine-grained, well sorted sands which don't include the smaller grains more than silt-sized. They show characteristic hummocky stratification. The sheet sands by storm-ge … More nerated turbidity currents are deposited in the deeper environment than storm wave base.3) The general relationship between wave condition and outbreak of liquefaction of soil layer was deduced. The examination of the relationship indicated that the outbreak of liquefaction is affected more by coefficient of pore pressure than by the efficient of compaction.4) To research the liquefaction and effusive sand in the soil layer intercalated with clay layer, the model experiment vibrated forcely was made. The result showed dynamic water pressure with vibration, which indicates the dynamic flow of the soil as liquid, is observed at the liquefied stage, and that the resistance of clay layer accelerates the liquefaction.5) The movement of sands under the condition coexisting wave and turbidity is examined in terms of probability using the Fokker - Planck equation. The result indicated that the distribution of transportation distance is the Gauss distribution in which the distance is increased as time. Less