Study of Oceanic Wave and Submarine Mass Movement

本课题的目的是为了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、质量运动和砂体运移的现象和过程。主要研究结果如下：1)通过对相模湾、苏鲁加湾和色藤内海海底土壤剖面特征的研究，发现沉积物剖面可以用颗粒假设下的简化方程很好地表达。利用这些方程，可以用含水率、孔隙率、不排水抗剪强度、无侧限抗压强度和有效超载压力来预测沉积物剖面。2)在地质和历史时期，由风暴波引起的大量移动的沉积物是细粒到非常细粒、分选良好的沙子，其中不包括大于粉砂尺寸的更小的颗粒。它们表现出典型的丘陵状层理。由Storm-ge…制作的床单沙子3)推导了波浪条件与土层液化爆发的一般关系。结果表明，孔压系数比压实系数对液化爆发的影响更大。4)为研究粘土层夹层中的液化和喷砂问题，进行了振动模型试验。结果表明，在液化阶段观测到了振动动水压力，表明土作为液体的动态流动，粘性土层的阻力加速了液化。5)利用Fokker-Planck方程对波浪和浊度共存条件下砂土的运动进行了概率分析。结果表明，运输距离服从高斯分布，且随着时间的推移，运输距离呈递增趋势。较少

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