土石流の停止・堆積機構に関する研究 (1) -勾配の急変による堆積-

Abstract

Stoppage and deposition of debris flows due to an abrupt flattening of channel slope aretheoretically and experimentally studied.A critical slope is defined as a function of concentration, angle of repose and densities of debrisand water. On a channel steeper than that slope debris can flow without any deposition. Thecapacities of the conveyance of the channels in such cases are discussed.Another critical slope, on a channel flatter than which a debris flow deposits with that slopeangle is obtained. This critical slope is a function of water discharge in the debris flow and the phy-sical properties of the deposit. Depositting processes in such cases are mathematically modeled.A debris flow can flow with partial deposition on the channel of which slope is between thetwo critical slopes. The process of channel bed variation in such a case is also treated.Theoretically obtained results are proved valid by the experiments.