Formation Law of Frozen Wall in Shafts of Neritic Stratum with High Salinity: Ice Water Phase Transition Model and A Case Study

This article uses COMSOL numerical simulation software to construct a flow–heat coupling model considering phase transition effects, and systematically explores the evolution law of the artificial freezing temperature field in a single-ring uniform annular hole layout scheme under the action of high-salinity groundwater with different flow velocities. The research results indicate that under the action of the groundwater seepage field, there will be a cold transfer effect around the freezing holes, which promotes the cold to shift and accumulate downstream of the water flow. In the entire freezing ring, the transfer of cold energy first accumulates in the frozen areas on both sides of the freezing ring and generates freezing walls. After the formation of the frozen walls, they first develop symmetrically toward the frozen area in the downstream area. This freezing stage takes 89.74-95.75% of the total time required for the frozen ring to completely close and is the main stage of the freezing process. After the two frozen walls intersect and close in the frozen area in the downstream area, the frozen walls quickly advance toward the frozen area in the upstream area until the entire freezing ring closes. This stage only takes 4.25-10.26% of the total time. This study reveals the main evolution laws of the artificial freezing temperature field under the influence of high-salinity groundwater seepage, which can provide theoretical reference for the optimization of freezing schemes and the prediction of the construction period in related projects.