Numerical Simulation of the Influence of Salt Content on the Freezing Effectiveness of Sand

During the freezing construction of saline soil， salt content is a key factor affecting the freezing efficiency. In order to explore the cooling process of sand layer freezing under different salt contents and the influence of salt content on the development of frozen bodies， a numerical simulation model of double-hole freezing of salt-bearing sand layers was established using COMSOL software， focusing on analyzing the freezing temperature field and the development characteristics of frozen bodies. The model comprehensively considers the influence of salt content on freezing temperature， thermal conductivity， specific heat capacity， and unfrozen water content， and the simulation results were compared with experimental data. The results showed that the presence of salt altered the cooling rate of the sand layer. Moreover， due to the lowering of the freezing temperature， the time required for freezing to close （closure time） was significantly prolonged， and the thickness of the frozen wall was noticeably reduced. In addition， variation curves of the freezing temperature， closure time， and frozen wall thickness with respect to the salt content of the sand layer were fitted. Empirical formulas of these important indexes and the salt content of the sand layer were compared and calibrated against the test results to enhance their practical reference value， thereby providing guidance for the construction of the freezing method in saline formations.