Abstract
After the Tohoku Pacific Ocean Earthquake in 2011, GRS (Geosynthetic-Reinforced Soil) coastal dykes are proposed to be strong dykes against overflow of tsunami. The authors have studied the resistibility of GRS coastal dykes against overflow through hydraulic experiments with several types of GRS coastal dykes. The authors showed that shape of GRS coastal dykes and inner structure of them affect the resistibility of overflow. But the mechanism of improving resistibility of GRS coastal dykes are still not realized. In this research, the authors conducted a series of hydraulic experiments on the resistibility of geogrid covering the surface of GRS coastal dykes against erosion. The results of experiments showed that laying geogrids on the surface of the ground was remarkably effective in decreasing erosion of geo-materials. In addition, it was proved that geo-material erosion with geogrid cover was related to the grain size of adjacent geo-materials.
