A Research on the River Bed Resistance of Chiyoda Experimental Flume

Abstract

2正会員 工博 (独)土木研究所寒地土木研究所(〒062-8602 札幌市豊平区平岸1条3丁目) 3正会員 Ph.D (独)土木研究所寒地土木研究所(〒062-8602 札幌市豊平区平岸1条3丁目) 3非会員 工学 国土交通省北海道開発局帯広開発建設部(〒080-8585 帯広市西4条南8丁目) Authors did a movable bed and steady flow experiment at the Chiyoda Experimental Flume, a large scale flume located in the Chiyoda New Waterway of Tokachi River, and observed bed wave figure on the local bed materials. In this study, the steepness of the sand waves observed was first estimated using the Yalin-Karahan method, and found that the observed was only slightly less than the estimated value. Next, the normalized bed shear stress and normalized grain shear stress calculated from the observed values were compared, and were found to have similar tendencies as seen in the results of Kishi and Kuroki based on the hydraulic radius separation method. The bed shear stress was also estimated by calculating grain stress and form drag directly from sand wave forms with reference to the method of Kikkawa and Ishikawa etc., and the estimated values were found to be slightly smaller than the observed values.

Overtopping‐Induced Failure of Non–Cohesive Homogeneous Fluvial Dikes: Effect of Dike Geometry on Breach Discharge and Widening

“…The breaching of fluvial dikes exhibits distinct features than those involved in embankment dams (ASCE/EWRI Task Committee on Dam/Levee Breaching, 2011). This includes complex 3D flow structures involving spiral flow in the breach (Michelazzo et al, 2015), non-symmetric breach expansion and impinging jet erosion (e.g., Elalfy et al, 2018;Kakinuma et al, 2013;Rifai et al, 2017).…”

“…Field-scale observations of fluvial dike breaching remain scarce, due to the difficulty in setting up largescale tests, controlling boundary conditions and recording accurate measurements. To our knowledge, only Kakinuma et al (2013) conducted four field tests of overtopping of 3 m high dikes made of sand and gravel. The dike composition, crest width, and inflow discharge in the main channel were varied.…”

Construction of depth-discharge relation for inundation simulation

“…relation with linear and weakly nonlinear analysis. Experimental research was also conducted in the Chiyoda experimental channel of the Tokachi River to observe bed form in a controlled environment (Kakinuma et al, 2013). Observed data at the Ishikari River during a flood in August 1981 was analyzed in terms of the ' * *    relation (Hirai et al, 2014).…”