Experiments on Rockfall Protection Embankments with Geogrids and Cushions

There are various protection measures against rockfalls. An embankment is effective in rockfall hazard mitigation at a dangerous slope end. The slope rockfall tests on full-scale embankments have been carried out. These embankments are made of sandy soil reinforced with geogrids. The cushioning layers which are made of geocells filled with crushed stones of 5-13 mm in diameter are also placed on the mountain side of the embankment. A boulder, i.e., RC block rolls down the test-site slope, and hits against the embankment. A new system of measuring instruments is employed in order to evaluate the impact force and the impact energy. One of important observations is a possibility that a rolling boulder carries it toward the top of an embankment because of its rolling momentum. The experimental results, especially the relationship between impact force and impact energy is discussed in this paper.