Author(s): Jun Okuda; Yasuyuki Shimizu; Tomoko Kyuka
Linked Author(s): Yasuyuki Shimizu
Keywords: Revetment; Flume experiment; PIV analysis; Riverbed deformation
Abstract: In alluvial rivers, revetments have an important role in protecting banks and levees from lateral erosion. In general, revetments are designed and constructed in consideration of riverbed degradation and local scouring at a toe of a revetment. In 2016 August, numerous flooding events and countless revetment failures due to heavy rain are observed in tributaries of the Tokachi River in Hokkaido, Japan. One of the noticing points with those revetment failures in these events was that they were caused not only by local scouring in low-water channels, but by erosion on high-water channels. In this study authors focused on the mechanism of revetment failure caused by scouring along a revetment on high-water channel and carried out some flume experiments to replicate and examine these patterns of revetment failures. Results of experiments showed some points of view regarding revetment failures. In a straight channel, there is some possibility that a local scouring happens at the end of a revetment, inducing erosion on high-water channel along the revetment. On the other hand, in a meandering channel an overtopping and an erosion on high-water channel happened along a revetment and this erosion seemed to induce the revetment failure. Through a PIV analysis, this erosion was caused by not only a rapid overtopping flow along the revetment.