Rheological Characteristics and Run-out Simulation of Fine-Grained Soils with Sand Content and Liquidity Index

摘要

To evaluate effects of sand content and liquidity index(water content)on the rheological properties of fine-grained soils, several series oflaboratory tests were performed on specimens with various sandcontents of 0, 5, 10, and 15% or with various liquidity indices rangingfrom 5 to 12.3. The flow behavior was strongly influenced by liquidityindex(water content) and sand content. The overall shape of the flowcurves of specimens had characteristics of a shear thinning fluid, with adecrease in viscosity as shear rate increased. The yield stress andviscosity gradually decreased as the liquidity index increased. At agiven liquidity index, yield stress and viscosity of soil increased with anincrease in sand content. A two-dimensional flow model (FLO-2D) wasused to simulate a debris flow including flow depth, velocity andvolumetric sediment using rheological data collected in this study. Itwas found that velocity and run-out distance decreased as viscosity andyield stress increased. Numerical results indicated that flowcharacteristics of debris flow depended on viscosity and yield stress ofsoil.