【摘 要】
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Debris flows are a kind of rapid geomorphologic processes, which lies in the range of phenomena intermediate between sediment-laden water floods and landslides and are regarded as particular solid-liq
【机 构】
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Key Laboratory of Mountain Hazards and Earth Surface Processes, Chinese Academy of Sciences,Institut
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Debris flows are a kind of rapid geomorphologic processes, which lies in the range of phenomena intermediate between sediment-laden water floods and landslides and are regarded as particular solid-liquid two-phase flows.The liquid-phase is the slurry, which is composed by water and fine-particles in debris flows with intensive mixing and behaves as a non-Newtonian fluid simulated by Bingham model or Herschel-Bulkley model.The solid-phase is consisted of coarse-particles in debris flows.The friction and collision between coarse-particles cause the loss of kinetic energy of debris flows and slow down the motion of debris flows.For solid-particles in debris flows, the rheology model is often considered to be a qualified dynamic model.Recently, theμ(I)-rheology model of granular flows was proposed by G.D.R.MiDi (2004), which is phenomenological one fitted by data of experiments and numerical simulations, In this model, the friction coefficientμ increases with I, which is called the inertial number representing the relative importance between inertial stress of particles and imposed pressure.In theμ(I)-rheology model the volume concentration of solid-particles could not be directly solved with governing equation due to the absence of state equation.In the present study, we have re-investigated the characteristics of solid-liquid two-phase flow of debris flows and the properties ofμ(I)-rheology model.The results show thatμ(I)-rheology model may not be the best model to describe the dynamics of debris flows.On the other hand,the frictional-collisional rheology models have provided a clear physical meaning and are able to describe the friction and collision between solid-particles separately.The comparisons to the available experimental data also support the use of the proposed frictional-collisional rheology models.
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