Author(s): Kakinuma Takaharu; Tobita Daisuke; Shimizu Yasuyuki
Linked Author(s): Yasuyuki Shimizu
Keywords: Chiyoda experimental flume; Levee breach process; Quantification of levee breach; Numerical model
Abstract: The flood damage is particularly severe when levee breaches occur, so estimating the flood magnitude and providing hazard maps are crucial for risk management. In light of this, the authors identified an urgent need to clarify the mechanism of riverine levee breach. The purpose of this study is to clarify the mechanism of riverine levee breach and propose a numerical model to predict breach speed and overflow rate. The authors performed large-scale experiments of overtopping breach using an experimental flume located on the floodway of the Tokachi River, and found out the correlation between the breached volume and Shields number. Next, the authors modified the conventional two dimensional model by integrating the experiment results into geomechanics of the model, and obtained a fine result of reproducing the breach widening speed. Finally the authors applied the model for an actual breach occurred in 2013 in Japan, and obtained a fine result of reproducing the breach widening speed.