open access

https://hdl.handle.net/2115/68834

Sensitivity of Clay Suspension Rheological Properties to pH, Temperature, Salinity, and Smectite-Quartz Ratio

英語

2017-10-16

American Geophysical Union

Geophysical research letters

44(19)

9615-9621

Understanding the rheological properties of clay suspensions is critical to assessing the behavior of sediment gravity flows such as debris flow or turbidity current. We conducted rheological measurements of composite smectite-quartz suspensions at a temperature of 7 degrees C and a salt concentration of 0.6M. This is representative of smectite-bearing sediments under conditions on the seafloor. The flow curves obtained were fitted by the Bingham fluid model, from which we determined the Bingham yield stress and dynamic viscosity of each suspension. At a constant smectite-quartz mixing ratio, the yield stress and the dynamic viscosity tend to increase as the solid/water ratio of the suspension is increased. In the case of a constant solid/water ratio, these values increase with increasing smectite content in the smectite-quartz mixture. Additional experiments exploring differing physicochemical conditions (pH1.0-9.0; temperature 2-30 degrees C; and electrolyte (NaCl) concentration 0.2-0.6M) revealed that the influence of temperature is negligible, while pH moderately affects the rheology of the suspension. More significantly, the electrolyte concentration greatly affects the flow behavior. These variations can be explained by direct and/or indirect (double-layer) interactions between smectite-smectite particles as well as between smectite-quartz particles in the suspension. Although smectite is known as a frictionally weak material, our experimental results suggest that its occurrence can reduce the likelihood that slope failure initiates. Furthermore, smectite can effectively suppress the spreading distance once the slope has failed.

学術雑誌論文

Version of Record

An edited version of this paper was published by AGU. Copyright 2017 American Geophysical Union. Kameda, J., & Morisaki, T. (2017). Sensitivity of clay suspension rheological properties to pH, temperature, salinity, and smectite-quartz ratio. Geophysical Research Letters, 44, 9615–9621., DOI:10.1002/2017GL075334. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

0094-8276

1944-8007

AA00657102