Een experimentele studie betreffende het vergrotingsproces van rivierdijkbreuken (EXPERIMENTS ON ENLARGING PROCESS OF RIVER BANK BREACHES)

Abstract

Vertaling van een origineel Japans rapport naar the Nederlands. Flood damage due to a bank breach increases with a river water inflow through it, which is enlarged by a hydraulic action of the inflow, while the influx rate is controlled by the geometry of the breach as weil as the stage and discharge of the river. For the purpose of predicrion on flooding inside the bank and mitigation of the damage, this process needs to be investigated to estimate the influx rate and to find out a efficient closure technique. We carried out fundamental experiments, and describe tbe enlarging process of modeled bank breaches as the results in detail, such as cbanges in geometrical characteristics, influx rates, water stages at tbe both sides of the bank models and their seepage states. These results were discussed on bydraulic properties at tbe breach, tbat is, flow resistanse, sediment transport, stage-discharge relationship between the water stage outside and the influx rate. lt is found out that the process has four enlarging phases, The first one is finished wben carving of initial failures, which are V·shaped grooves at the top of banks, reaches the outside slopes. During the second, scouring downward and widening of the breaches progress rapidly and increase in influx rate is very large. Gradual widening only continues at the third one and inflow increases a little. Finally, geometry and influx rate beoome rather constant in the fourth phase.KWP-collectio