Experimental Study on the Viscoelastic Behaviors of Debris Flow Slurry

The rheological properties of most liquid in nature are between liquids and solids, including both elastic changes and viscosity changes, that is so-called "viscoelastic". Dynamic oscillatory test was used to quantitatively study the distinct viscoelastic behaviors of debris flow slurry in the shear stress conditions for the first time in this study. The debris flow slurry samples were from Jiangjiagou Ravine, Yunnan Province, China. The experimental results were found that at the low and middle stages of shearing, when the angular velocity ω < 72.46 s^-1, the loss modulus (G") was greater than the storage modulus (G'), i.e. G" > G'. At the late stage of shearing, when the angular velocity ω≧72.46 s^-1, the storage modulus was greater than or equal to the loss modulus, i.e. G'≧G", tanδ≦1 (where phase-shift angleδ=G"/G'), and the debris flow slurry was in a gel state. Therefore, the progress of this experimental study further reveals the mechanism of hyperconcentrated debris flows with a high velocity on low-gradient ravines.