抄録
The damage to a dike caused by high water levels from a localized torrential downpour over a long period is presumed to be related to dike saturation from the seepage water from the dike surface and the blow off of pore air following a movement in the seepage line in the dike. The water flow generates a large-scale scour around the structure, and as a result, the stability of the structure is decreased. We discuss the ways in which multi-scaling problems and multi-phase interactions between soil, water, and gas affect these structures in three types of fundamental scour experiments. This study attempted to elucidate the scouring mechanism by experimenting using a movable bed channel device. During the water flow acting on the ground, a vertically upward hydraulic gradient along with excess pore water pressure was generated in the saturated ground, and a liquefaction-like phenomenon was generated by an increase the excess pore water pressure in the ground. Consequently, scouring was facilitated. The pore air in the unsaturated ground formed an air bubble due to seepage flow, and it spouted in the ground surface. The importance of the scour phenomenon of the dynamic interaction of soil particles, pore water, and pore air was discovered.
