Development of a Temperature-Controlled Direct Shear Box for Frozen Samples
Date
2023-03-23
Authors
Emami Ahari, Hossein
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American Society of Civil Engineers
Abstract
Global surface temperatures rose by 1°C in 2020 relative to the average temperatures between 1951 and 1980. A reduction in the extent of the almost 24% of the Northern Hemisphere covered by permafrost will impact the stability of new and existing civil infrastructure in the area. Frozen soil is a multi-phase system consisting of ice, unfrozen water, air, and soil particles. Fluctuations in temperature change the proportions of the constituents significantly impacting the strength of the soil mass. The strength behavior of fine-grained soils will differ substantially from that of frictional soils since fine-grained soils can have high ice contents due to their high-water absorption capacities. However, the lack of commercially available equipment has deterred research efforts in understanding the impact of climate change on the shear strength properties of fine-grained soils. This paper describes the development of a new direct shear box that allows for temperature-controlled testing. Modifications to the temperature-controlled shear box as deemed necessary from validation tests are also described. For example, comparisons of the temperature measurements within the soil sample to the chilled glycol circulating in the modified direct shear box indicated that additional insulation had to be provided to the apparatus. The freezing mechanism applied to the soil sample affected the distribution of ice within the pore spaces and illustrated the need to freeze the sample from all directions. This was incorporated into the modifications that were designed in this study. Shear strength parameters from the newly designed temperature-controlled direct shear box matched well with those from the traditional shear box.
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Comments
This is a manuscript of a proceeding published as Emami Ahari, Hossein, and Beena Ajmera. "Development of a Temperature-Controlled Direct Shear Box for Frozen Samples." In Geo-Congress 2023, pp. 262-272.
This material may be found at DOI: 10.1061/9780784484678.027.
This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers.
Copyright 2023 American Society of Civil Engineers.
Posted with permission.