Geotechnical characterization of an artificially frozen soil with an advanced triaxial apparatus

The excavation of tunnels in medium to high permeability soils below the groundwater level requires the provision of temporary support and the adoption of techniques to exclude the groundwater from the excavation. Artificial Ground Freezing (AGF) is a technique that provide waterproofing and strengthening to the frozen soil body with minimal impact on the surrounding environment. This paper presents the preliminary experimental results obtained using an advanced triaxial apparatus (FROZEN), working under temperature and stress path controlled, to test a silty soil sample retrieved from a railway construction site. The apparatus allows the application of the thermal loading from a probe installed in the centre of the sample, so that the frozen front propagates from the centre of the sample to its boundary, similar to the conditions experienced in situ during the AGF implementation.