Mechanical Behaviour of Artificially Frozen Ground: Experimental Observations and Modelling

Artificial Ground Freezing (AGF), a newly developed system used as a temporary ground improvement, has been successfully exploited for underground construction under different geotechnical conditions and all over the world. This success is mainly due to its minimal impact on the environment as well as to the progress made in the understanding of the behaviour of frozen soils. Owing to the strong non-linearity of the governing equations, and their reciprocal coupling, the analysis of the Thermo-Hydro-Mechanical (THM) coupled behaviour of frozen soils requires the adoption of numerical techniques. Constitutive models for the behaviour of frozen ground have been developed and implemented with various degrees of sophistication, depending on their particular application purposes. However, a solid framework including also transient effects has yet to be established for fully coupled THM approaches and there is still scope for fundamental research to be carried out on experimental characterisation and constitutive modelling of frozen/unfrozen ground.