Excavation countermeasures utilizing geocell at the foundation ground of the river embankment

The embankment of the Kinugawa River collapsed in 2015, causing serious damage. It is ideal that river embankments are strong enough to resist overflow and washout. However, it is extremely difficult to develop structures that will neither allow overflowing nor break down, due to cost and plots. Therefore, it is necessary to promote the development of a tenacious river embankment, which can be re-inforced with a low cost, in order to delay the washout even if the river overflows the embankment. By improving the tenacity of the embankment, we can earn time to evacuate in the event of a disaster. One of the factors that cause the collapse of the embankment after the overflow is excavation of the foundation ground of the slope toe of the embankment reverse side. A plan has been drawn to reinforce the founda-tion ground with large concrete blocks. However, it is considered that reinforcement of the foundation ground only with concrete blocks is not enough. Under such circumstances, it is considered that rein-forcement using geosynthetics materials is effective. In the past studies, it has been confirmed that we can reduce excavation of the foundation ground by using geosynthetics materials. In this study, we conducted a comparative experiment on a reinforced case made of blocks only and a reinforced case combining blocks and geosynthetics materials. As a result, it was confirmed that the tenacity of the slope toe of the embankment reverse side was significantly improved by using the geosynthetics materials.