Abstract
The recent developments of human activities in marine environments are stimulating engineering concerns on natural hazards in the sea. One of the hazards in the marine environments is a failure of submarine slopes which is caused by earthquakes, wave action, rapid sedimentation, etc. The submarine soil flow as a consequence of slope instability is possible to be of gigantic scale, and affects artificial facilities in vast area, requiring them to be well protected against soil's attack. A series of model tests were carried out to understand the intensity of the drag force which is brought about by a mudflow on a cylindrical solid column. The test results indicate that the intensity of the drag force is proportional to the embedment and diameter of the column, while practically independent of the flow velocity. Since the water content of flowing soil was found to be playing an important role, its effects were accounted for through undrained shear strength of soil. The shear strength of very soft slurry employed here was evaluated either by a model-footing test or by an empirical equation, both of which gave identical results. Eventually an empirical equation is proposed to predict the magnitude of the drag force exerted by a flow of clay slurry.
