کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4915021 | 1427731 | 2017 | 7 صفحه PDF | دانلود رایگان |
- Mud slurry has no evident effects on the frictional coefficient of coarse particles.
- Mud slurry can decrease flow resistance of the particles through fluidization.
- The effect is more notable at higher shear rates or with more concentrated slurries.
Laboratory experiments were performed to investigate the effect of mud slurry on the flow resistance of cohesionless particles in debris flow. For one thing, natural angles of repose were measured for the gravel materials resting in air, in water, and in mud slurry separately. For another, rheological tests were taken using a vane rheometer to measure the torque-time response of sand particles within mud slurries of varying solid concentrations both at low and high rotational speeds. The stable torque obtained at the low rotational rate, which represents flow resistance primarily caused by particle contact friction, was nondimensionalized to compare the internal friction coefficient in each case. Furthermore, flow resistance of sand particles within one of the mud slurries was measured over a wide range of rotational speeds to compare with that in the dry system. It was found that the mud slurry has no significant effects on the frictional coefficient of cohesionless coarse particles. However, the mud slurry tends to decrease flow resistance of the particles, with the effect being more significant at higher rotational speeds or for more concentrated slurries. This derives from excess pore fluid pressure, which is easier to maintain at higher shear rates or within more cohesive slurries.
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Journal: Powder Technology - Volume 310, 1 April 2017, Pages 1-7