Abstract: This study addresses the technical challenge of closing the freezing wall in saturated sand layers under strong seepage conditions by proposing a combined grouting and freezing method. A dual-hole grouting-freezing model test was conducted to systematically investigate the effects of seepage velocity and refrigerant temperature on the freezing characteristics of the grout-matrix composite. The test results indicate that: (1)The seepage field significantly delays the development of the freezing temperature field. Increased seepage velocity results in an overall temperature rise of the freezing field,with the temperature near the freezing pipes being dominated by the refrigerant,while the temperature at the distal end is controlled by seepage. (2)Higher seepage velocity reduces the thickness of the freezing wall of the grout-matrix composite upstream and downstream,prolongs the closure time,increases the average temperature of the frozen body,and causes the shape of the freezing wall to shift downstream. (3)Lower refrigerant temperature increases the thickness of the freezing wall,shortens the closure time,reduces the average temperature,and effectively improves the uniformity of the freezing effect. Furthermore,field monitoring results from a Tianjin metro connection tunnel validate the feasibility of this grouting-freezing combined technique under similar geological conditions. This study reveals the coupling mechanism of seepage and freezing and proposes the synergistic optimization of freezing effectiveness through refrigerant temperature regulation and grouting to retard seepage. The findings provide a theoretical basis for the combined grouting and freezing construction method in strata with strong seepage.