Confined and unconfined compression tests on frozen sands

The design of foundations in permafrost, excavation of frozen ground, and artificial freezing of ground to provide temporary support during construction of tunnels and other underground structures require understanding of the mechanical properties of frozen soils. This paper describes the equipment and procedures developed by the authors to determine the compressive strength of artificially frozen sands under confined and unconfined conditions at different temperatures and strain rates. A comparison of the results obtained under various conditions is made to assess the effects of testing conditions on the strength, strain at failure, and deformation behaviour of frozen sand. This comparison should assist in the standardization of laboratory testing procedures for the determination of the mechanical properties of frozen soils.La conception des fondations dans le perg\ue9lisol, l'excavation dans le sol gel\ue9 et la cong\ue9lation artificielle du sol pour fournir un appui temporaire pendant la construction de tunnels et autres structures souterraines n\ue9cessitent une connaissance des propri\ue9t\ue9s m\ue9caniques des sols gel\ue9s. Cette communication d\ue9crit l'\ue9quipement et les m\ue9thodes d\ue9velopp\ue9s par les auteurs pour d\ue9terminer la r\ue9sistance \ue0 la compression des sols gel\ue9s artificiellement tant dans des conditions confin\ue9es que sans confinement lat\ue9ral, \ue0 des temp\ue9ratures et vitesses de d\ue9formation diff\ue9rentes. On compare les r\ue9sultats obtenus dans diverses conditions afin de pouvoir \ue9valuer les effets des conditions d'essai sur la r\ue9sistance, la d\ue9formation \ue0 la rupture et le comportement de d\ue9formation du sable gel\ue9. Cette comparaison devrait aider \ue0 normaliser les m\ue9thodes d'essai en laboratoire servant \ue0 d\ue9terminer les propri\ue9t\ue9s m\ue9caniques des sols gel\ue9s.Peer reviewed: YesNRC publication: Ye