Application of Thermal Soil Freezing for Temporary Self-Support in Mining Tunnel Construction Across Saturated, Sandy, Clayey, and Silty Rock Formations

Sumiri-Mantilla F.R.; Guillén-Guillén R.; Retamozo-Belsuzarri J.F. · Proceedings of the LACCEI international Multi-conference for Engineering, Education and Technology (2024) · DOI: 10.18687/laccei2024.1.1.1647

Resumen

The present study encompassed the application of the thermal method of artificial ground freezing in sandy, clayey, and silty soils for temporary self-support in mining tunnels. A numerical thermo-hydrogeological simulation was conducted using the Plank cooling equation and thermodynamic principles. It was determined that clays require twice the amount of heat extraction compared to sand to reach the optimal temperature, demonstrating an inverse relationship between saturation percentage and freezing time. By considering three refrigerants, it was found that liquid nitrogen is capable of freezing 77% faster than brines. The self-support time of a rock mass was calculated and compared before and after applying the method, showing that artificial freezing enables the creation of temporary self-support in mining tunnels with a roof width exceeding 3.8 meters, with an estimated duration of less than 12 years; where for narrower roof widths, no additional reinforcement is required.

Instituciones: Universidad Tecnológica del Perú