Advanced apparatus to perfom triaxial tests on Artificially Ground frozen
Introduction
FROZEN is a triaxial apparatus able to perform tests under temperature controlled conditions below zero degree centigrade. The system has been designed at DICII (in collaboration with UPC Barcelona). FROZEN has been developed to study the thermo-hydro-mechanical behavior of soils subject to freezing and thawing. The application of the thermal load takes place from the inside of the sample to the outside reproducing the thermal path occurring on site during the application of Artificial Ground Freezing.
Technical features
Device composed by three main components reported in Figure: 1) mechanic loading system (press); 2) triaxial cell, the main novelty of the apparatus properly designed; 3) freezing system able to circulate refrigerant fluid at controlled temperature. The main innovation of FROZEN is represented by the method of applying the thermal load in radial direction, from the center of the sample to the outside (Bartoli et al 2018; 2019). INNOVATION: comprehension and optimization of the velocity of the frozen front propagation applying the temperature with the same in situ radial direction. The main aim is to optimize AGF, which is the only sustainable method to temporary support for excavation.
Possible Applications
- Geotechnical characterization of artificially frozen soils (AGF);
- Artificial Ground Freezing is used as temporary support and waterproofing method in civil engineering applications such as:
-
- Tunneling and underground constructions;
- Main stations and shaft;
- Barriers to contain nuclear waste.
Advantages
- Radial thermal load;
- Monitoring of temperature at various distance;
- External position of water drainage;
- Axial loading under stress path and strain controlled;
- Monitoring of radial displacement by means of local transducers.