Rheological properties of fine-grained soils according to temperature and water content

The rheological properties of fine-grained soils, which are greatly affected by temperature and water content, are some of the most important factors for the reduction of debris flow damage. In this study, the variation of rheological properties is investigated on fine-grained soils according to temperature and water content. After the rheological properties of fine-grained soils are evaluated by rheometer, the plastic viscosity and yield stress of fine-grained soils are calculated based on the Bingham model. The plastic viscosity and yield stress of the specimens with three liquid indices (1.0, 1.5, and 2.0) are evaluated at different temperature conditions (15°C~35°C). The rheometer test results show that the plastic viscosity and yield stress of fine-grained soils at high temperature are smaller than those at low temperature. The plastic viscosity and yield stress of fine-grained soils decrease with an increase in the liquid index. The fine-grained soils at 15°C have twice higher plastic viscosity than those at 35°C. This study demonstrates that debris flow under the conditions of high temperature and high water content may have lower plastic viscosity and lower yield stress than that at low temperature and low water content.