Experimental Investigation of Rheological Behavior and the Viscous-Inertial Boundary in Dense Solid-Liquid Two-Phase Granular Flows

The dynamic natureprocesses of many geological disasters, such as debris flow and shallow landslides is, are essentially acharacterized by dense solid-liquid two-phase granular flowflows. Due to the complex interaction mechanism ofbetween the solid- and liquid phasephases, its rheological properties are extremely complex. The μ(I)The and constitutive models were proposed to describe the rheological behavior for dry granular flow and μ(J) constitutive models for flows and solid-liquid two-phase granular flow are proposed in particle physics.flows, respectively. However, these models are mainlyhave been proposed based on free surface flow or very low normal stress conditions (<(generally <1 kPa), and use ideal granular materials (e.g., plastic/metal/glass spheres), which have ). These conditions deviate significantly different stress ranges and material properties from those encountered in real surface hazards.-world geohazard scenarios. Therefore, the rotary we conducted experiments using a rheometer and self-developed experimental equipped with a designed shear chamber were used in this paper to achieve, capable of applying normal stress loading in the range of stresses ranging from 5 kPa to 20 kPa, and shear strain rates from 0.1 s⁻¹ to 360 s⁻¹ to granular materials under long -distance shear shear under the condition of 0.1 s-1-360 s-1 shear strain rate. Zirconium. We utilized zirconia beads/ and quartz sand as granular materials, and water/ and silicone fluid were usedas interstitial fluids to simulate the rheological properties of mineral materials in the range of real slurry viscosity. The experimentala range of solid-liquid two-phase flow conditions. Our results showdemonstrate that the high -viscosity interstitial fluidfluids significantly increasesenhance the friction coefficient of granular flowflows, especially under high-speed shear conditions. When. We find that the constitute effectively characterizes flow behavior when the viscosity of the dry granular flowmaterial or interstitial fluid is low, the μ(I) model can be used to while the constitute is more suitable for high-viscosity interstitial fluids. Based on these physical simulation experiments, we propose specific dimensionless boundary parameters to delineate viscous and inertial flow regimes. This distinction enables the selection of the appropriate constitutive law for accurately characterizemodeling the rheological properties, while when the viscosity of interstitial fluid is high, the μ(J) model is needed to characterize the rheological properties. Based on the results of physical experiments, this paper proposes specific dimensionless parameter values to divide the boundary between viscous and inertial particle flows, so that a reasonable constitutive model can be adopted under the conditions of different physical mechanisms to achieve a more accurate description of the macroscopic dynamic process of this kind ofdynamics of these geological hazardsflows.