Effect of medium-sized particle diameter and grading on yield stress of debris flow

Abstract

[Objective] Generally, the yield stress of debris flow is positively correlated with solid volume concentration and the enhancement of clay viscosity. It is also influenced by the properties of coarse particles as well. However, existing laboratory rheological experiments have not considered the influence of medium particle properties on yield stress. To investigate the influence of medium particle properties on yield stress and improve the yield stress calculation model, [Methods] the yield stress of debris flow was examined using four types of medium-particle quartz sand with different mesh sizes. By varying the solid volume concentration, medium particle size, and particle grading, debris flow slurry was prepared for laboratory rheological experiments, and the experimental data were statistically analyzed. [Results] Analysis and comparison result indicated that better medium particle grading result ed in lower yield stress, whereas poorer grading led to higher yield stress. When the solid volume concentration was C₀< 0.47, medium particle size had little effect on yield stress. When C₀≥0.47, medium particle size exhibited a negative correlation with yield stress. [Conclusion] The experimental result demonstrate that modifying medium particle grading and size, based on coarse particle studies, resulting a new volume concentration correction coefficient. This refinement further improves the yield stress calculation model, enhancing its scientific accuracy and reliability.

Keywords

debris flow / yield stress / particle diameter / grading / shape / influence factors