Modeling Seepage Flow and Spatial Variability of Soil Thermal Conductivity during Artificial Ground Freezing for Tunnel Excavation

Artificial ground freezing (AGF) technology has been commonly applied in tunnel construction. Its primary goal is to create a frozen wall around the profile as hydraulic barrier and temporary support, but it inevitably affected by two natural factors. Firstly, seepage flows provide large continuous heat energy prevent soil from freezing. Secondly, key parameter transfer, thermal conductivity shows inherent spatial variability, binging uncertainties effects efficiency. However, few studies have explored influence of spatially varied on AGF. In this study, coupled hydro-thermal numerical model was developed examine formation wall. The simulated lognormal random field analyzed groups Monte-Carlo simulations. results confirmed adverse effect groundwater flow wall, including uneven development body towards downstream side higher risk water leakage upstream face tunnel. Based finite element analysis, study quantitively tabulated required additional time above deterministic scenario. Two levels are provided, namely average level conservative level, which aim facilitate practitioners making rule-of-thumb estimation design comparable situations. findings can offer rule thumb for estimating times needed artificial freezing, accounting variation conductivity.