Mechanics of Debris Flow Over a Rigid Bed
Kuniaki Miyamoto* and Yuki Tsurumi**
*Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-no-dai, Tsukuba City, Ibaraki 305-8572, Japan
**CTI Engineering Co., Ltd., 1047-27 Onigakubo, Tsukuba, Ibaraki 300-2651, Japan
Up to the middle of the 20th Century, debris flow was a little understood phenomenon. Since then, much has been done to understand it, including observations, experiments, and theoretical considerations. Studies on constitutive equations contributed much to understanding debris flow. These include a constitutive equation set proposed by Egashira, et al. that seamlessly explains a wide range of sediment-laden flow from debris flow to typical bed-load laden flow. These results mainly considered flow over erodible beds, with little systematic study on those over rigid beds. Using the constitutive equation set, we classify the regime for debris flow over rigid beds, and the characteristics of low concentration flow are discussed. Result suggest that some nondimensional criteria characterize the flow regime. While consider the low concentration regime is not enough to predict particular flows yet, it gives us an approach to understand the flow mechanism.
-  K. Miyamoto and S. Egashira, “Mud and Debris Flow,” J. of Hydroscience and Hydraulic Eng., No.SI-2, pp. 1-19, 1993.
-  R. A. Bagnold, “Experiments on a Gravity free Dis-Persion of Large Solid Spheres in a Newtonian Fluid Under Shear,” Proc. Royal Society. A, 225, pp. 49-63, 1954.
-  S. B. Savage, “Gravity Flow of Cohesionless Granular Material in Chutes and Channels,” J. Fluid Mech., 92, Part 1, pp. 53-96, 1979 (in Japanese).
-  J. T. Jenkins and S. B. Savage, “A Theory for the Rapid Flow of Identical, Smooth, Nearly Elastic,” Spherical Particles, J. Fluid Mech., 130, pp. 187-202, 1983.
-  P. C. Jonhson and R. Jackson, “Frictional-Collisional Constitutive Relations for Granular Materials, with Application to Plane Shearing,” J. Fluid Mech., 176, pp. 67-93, 1987.
-  T. Tsubaki, H. Hashimoto, and T. Suetsugi, “Grain Stress and Flow Properties of Debris Flow,” Proc. JSCE, No.317, pp. 79-91, 1982 (in Japanese).
-  S. Egashira, K. Miyamoto, and T. Itoh, “Constitutive Equations of Debris Flow and Their Applicability,” Proc. 1st Int. Conf. on Debris-Flow Hazards Mitigation, New York: ASCE: pp. 340-349. 1997.
-  S. Egashira, “Review of Research Related to Sediment Disaster Mitigation,” J. Disaster Research, Vol.2, No.1, pp. 11-18, 2007.
-  K. Ashida, S. Egashira, and H. Nakagawa, “River Morphodynamics for the 21st Century,” Kyoto University Press, pp. 139-139, 2008 (in Japanese).
-  T. Suzuki, “Study on the Mechanism of a Debris Flows Flowing Over Fixed Beds,” Doctoral thesis submitted to Tokyo Univ., pp. 22-74, 2007 (in Japanese).
-  T. Itoh, “Study on Constitutive Equation of Debris Flow and the Application,” Doctoral thesis submitted to Ritsmeikan Univ., pp. 38-65, 2000 (in Japanese).
-  K. Miyamoto and T. Itoh, “Numerical Simulation Method of Debris Flow Introducing the Erosion Rate Equation,” J. of the Japan Soc. of Erosion Control Eng., Vol.55, No.2, pp. 24-35, 2002 (in Japanese).
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.