Tarajulik* works on establishing a better understanding of the impacts of climate warming on thermal and mechanical stability of saline permafrost. Saline permafrost is a ground material permanently below 0°C containing dissolved salts (salinity) in the unfrozen pore liquid. The salinity lowers the freezing point and saline permafrost can thus have strength and deformation properties of thawed ground, even at negative temperatures. It is a terrain particularly sensitive to temperature disturbances and a major geohazard.
Permafrost is one of the main natural concerns for infrastructure design and maintenance in Greenland. Due to difficult and expensive logistics involved, proper geotechnical investigations are mainly conducted for large construction projects (airports, harbors). For smaller infrastructure and housing, designs are based on local experience, sparse existing data, recommendations of Greenland Technical Organization and properties of ground materials from Denmark. This practice often leads to expensive or inadequate solutions, problems tracing liability for construction failures, and even abandoning projects when geological reality on the construction site significantly differs from expectations. The need for accessible data on permafrost soils in Greenland is thus great.
Within Tarajulik, we conduct standard and advanced permafrost soil classification of natural samples from four permafrost-affected communities in West Greenland: Sisimiut, Kangerlussuaq, Ilulissat and Qaanaaq. The choice of locations is guided by the effort to represent variation in soil parameters and permafrost conditions in Greenland. The analysis includes grain size distribution, mineralogical composition, consistency limits, soil densities (bulk and dry), water content, ice content and thaw strain on undisturbed core samples. The results of the classification will be published in a freely accessible web-based database for the benefit of engineers and stakeholders in Greenland, and scientists worldwide.
With further climate warming, the compromised mechanical strength of warming saline permafrost will have a significant impact on stability of infrastructure built on it. Ground thermal models can help forecasting the thermal degradation, when properly calibrated. Therefore within Tarajulik, we also collect experimental data for parameterization of a model of heat transfer in frozen soils of various salinities. The improved thermal model is expected to lead to more reliable ground stability predictions.
The main outcomes of Tarajulik will be:
- Improved prediction capacity for thermal and mechanical stability of saline permafrost;
- Development of the experimental setup for advanced thaw strain measurements;
- Database of consistently-measured geotechnical properties and thaw consolidation potential for typical Greenlandic soils.
The project is hosted by the Technical University of Denmark in Lyngby, Asiaq Greenland Survey in Nuuk, Arctic DTU - Campus Sisimiut and Tech College Greenland (KTI) in Sisimiut.
*Tarajulik means containing salt in the West Greenlandic language.
Duration of the project:
2019-2022
Funding agency:
Nunatsinni Ilisimatusarnermik Siunnersuisoqatigiit (the Greenland Research Council)
Project partners and collaborators:
DTU, Asiaq Greenland Survey, Arctic DTU - Campus Sisimiut and Tech College Greenland (KTI) in Sisimiut.
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