| Title | Permafrost geotechnical index property variation and its effect on thermal conductivity calculations |
| Author | Brooks, H; Doré, G; Smith, S L |
| Source | Cold Regions Science and Technology vol. 148, 2018 p. 63-76, https://doi.org/10.1016/j.coldregions.2018.01.004 |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20170214 |
| Publisher | Elsevier |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Northwest Territories; Yukon; Alberta |
| NTS | 107; 106; 96; 95; 105I; 105P |
| Area | Mackenzie River Valley |
| Lat/Long WENS | -136.5000 -118.0000 69.0000 59.7500 |
| Subjects | surficial geology/geomorphology; permafrost; boreholes; statistical methods; statistical analysis; coefficient of variation (COV); soil and ice classifications |
| Illustrations | location maps; graphs; histograms; plots; tables |
| |
| Program | Permafrost, Climate
Change Geoscience |
| Abstract | Geotechnical borehole and sample data from three databases compiled by the Geological Survey of Canada were analyzed to determine the variability of geotechnical index properties within frozen soils.
The analysis included 2662 boreholes with geological setting data, up to 60?m depth, within the Mackenzie Valley and Delta region of the Northwest Territories. A total of 7539 samples, each with soil and ice classifications and gravimetric moisture
content data were included. Gravimetric and volumetric moisture contents were analyzed by general soil type to determine their coefficient of variation (COV) with depth and geologic setting. As expected, variability between geologic settings
corresponded to the nature of the soil's depositional environment, and volumetric ice content variability decreased with increasing depth. General soil type was also used to determine the COV for dry density, specific gravity, and Atterberg limits
for samples where testing was available. The variability of frozen thermal conductivities was estimated using Monte Carlo simulation and common equations from the literature based on the geotechnical index property variation. Recently-derived
equations for thermal conductivity showed less variability compared to earlier methods. |
| Summary | (Plain Language Summary, not published)
This paper utilizes information from over 2000 geotechnical boreholes in permafrost in the Mackenzie Valley NWT to characterize the statistical
variability of various index properties for representative terrain types. Properties considered included grain size, moisture content and ground ice content. The results of this work were utilized to better define the thermal properties for various
terrain types which can facilitate calculation of the range of thaw depths expected to occur due to climate variability and to define design values for infrastructure design. The results also support improved risk assessments and adaptation of
infrastructure to changing permafrost conditions resulting from a changing climate. |
| GEOSCAN ID | 305996 |
|
|