Vertical distribution of excess ice in icy sediments and its statistical estimation from geotechnical data (Tuktoyaktuk Coastlands and Anderson Plain, Northwest Territories)

Abstract

Excess ice, found as massive ice and within icy sediments, is an important variable to quantify as it is a dominant control on the terrain and geotechnical response to permafrost thaw. A large amount of permafrost borehole data are available from the Tuktoyaktuk Coastlands, however, field geotechnical assessments typically only involve the estimation of visible ice. To add significant value to these datasets, a cryostratigraphic dataset collected along the Inuvik-Tuktoyaktuk Highway (566 boreholes) is used to develop a beta regression model which predicts the excess ice content of icy sediments based on interval depth, visible ice content, material type, and Quaternary deposits. The resulting predictions are compared to recorded massive ice intervals and show that ground ice within icy sediments can contribute up to 65% of the excess ice and potential thaw strain within the first 10 meters from the surface in this area. This study shows the general applicability of this approach and indicates that comparable, quantitative data on ground ice conditions should be collected with drilling programs to derive geotechnical variables and reduce modeling uncertainties so that ground ice data are available for quantitative analysis.

Ice content in permafrost in the Kivalliq Region, Nunavut: digitization and analysis from historic drilling program

“…The percent visible ice content by volume is subject to expert interpretation, and therefore could have been under or over-estimated and inconsistently recorded by different technicians over the 3 years. For instance, even when assessed by current experts, estimated visible ice content may show unreasonable scatter and poor correlation against measured volumetric ice content (e.g., Castagner et al 2023). It is also possible that there is a scale mismatch between the two data types and the visible ice contents represent larger depth increments than the corresponding samples do.…”

“…However, if future ice content measurements are done for the region, it may still be possible to use regression models to produce a better result from visible ice content (cf. Castagner et al 2023).…”

Proceedings of the 12th International Conference on Permafrost: Volume 2 (Conference Papers)

“…This permits the calculation of their thaw strain (Pullman et al 2007;Crory 1973). However, thaw strain can also be derived from excess ice content (EIC) measurements (i.e., van Everdingen 2005) converted into a volumetric ratio of cumulative EIC to the total thickness of the thawed soil column (Castagner et al 2022). These data are often indispensable to predicting local GSS and possible infrastructure damage .…”

“…Construction of the highway sourced materials from seven borrow pits along the route. Materials were of variable quality, composed of unconsolidated silt, sand, and gravel sediment with significant ice content (Castagner et al 2022). It was expected that the roadbed would settle (consolidate) in the first several years following construction, requiring maintenance efforts during this time.…”

Ground ice content of the frozen active layer and near-surface permafrost in the Rankin Inlet area, Nunavut, Canada

“…This permits the calculation of their thaw strain (Pullman et al 2007;Crory 1973). However, thaw strain can also be derived from excess ice content (EIC) measurements (i.e., van Everdingen 2005) converted into a volumetric ratio of cumulative EIC to the total thickness of the thawed soil column (Castagner et al 2022). These data are often indispensable to predicting local GSS and possible infrastructure damage (Doré et al 2016).…”