Details

Autor(en) / Beteiligte

• Tounsi, H.
• Rouabhi, A.
• Jahangir, E.
• Guérin, F.

Titel

Mechanical behavior of frozen metapelite: Laboratory investigation and constitutive modeling

Ist Teil von

• Cold regions science and technology, 2020-07, Vol.175, p.103058, Article 103058

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Artificial ground freezing has been used in the mine of Cigar Lake to mitigate groundwater infiltration to underground mining operations and stabilize the heterogeneous and poor ground. In addition to the control of the freezing process, the ability to predict accurately the ground movements and the site stability is crucial to a successful use of this technique. This requires developing adequate constitutive models able to correctly reproduce the mechanical behavior of water-saturated soils at low temperatures. To achieve this goal, a digital control servo-hydraulic triaxial test facility with full data acquisition has been developed, and an experimental program was carried out to investigate the mechanical behavior of metapelite samples collected from the mine of Cigar Lake. A series of triaxial compression tests were conducted on reconstituted and natural frozen metapelite specimens under different strain rates (2.5, 4.5 and 8 × 10−6s−1) and at different temperatures (−10, −20 and −30 °C) and confining pressures (1, 5 and 9 MPa). The experimental results showed that the stress-strain behavior of frozen metapelite, in the studied range of temperature and confining pressure, is elasto-viscoplastic, strain hardening, highly sensitive to temperature and moderately sensitive to the confinement level. They also proved that the transition contractancy-dilatancy is significantly dependent on temperature and suggested the existence of a critical temperature between −20 and −10 °C that represents a dilatancy threshold. To capture these observations, a recent phenomenological model developed for crystalline rocks was used. The model accounts for the phenomena of hardening, dilatancy/contractancy and time dependency and was extended to include the effect of temperature on the frozen material's distorsion and on the dilatancy onset. The proposed model was validated using the triaxial compression tests on metapelite and experimental results from literature on frozen sand. •Triaxial compression tests were conducted on frozen reconstituted and natural metapelite samples under various conditions.•The e_ects of temperature, con_ning pressure and strain rate on the stress-strain behavior of frozen metapelite were analyzed.•An elasto-viscoplastic model allowing to capture the experimental observations was proposed.