Artificial ground freezing by solid carbon dioxide—Analysis of controlling factors on ice-wall formation

Artificial ground freezing using solid carbon dioxide is a novel, ecologically and environmentally friendly ground improvement technique aimed at ensuring the safety of underground construction projects in water-bearing soils where the traditional method of brine ground freezing is not feasible or practical. This innovative approach offers significantly lower temperatures, reaching as low as $-78.5°\text{C}$, resulting in a substantial reduction in ground freezing time and the ability to freeze soils with higher seepage rates. Wider adoption of this technology requires the minimization of construction costs and time. The aim of this study is to advance the design by analysing the underpinning factors affecting the formation of the ice wall and providing an assessment of the impacts of key geological and technological factors on the successful ice wall delivery. This is achieved through numerical modelling of heat and water transfer in soils, developed within the non-local framework of bond-based peridynamics. The approach presented enables the calculation of refrigerant consumption and forms the basis for an economic assessment of the technology. The results support the broader implementation of this ground improvement technique in engineering projects.