Abstract: Under conditions of strong seepage, the internal interaction mechanisms in combined grouting and freezing construction are complex, making it essential to study the coupled thermal-hydraulic behavior for practical engineering guidance. For the combined grouting-freezing construction in saturated sand layers, a coupled thermo-hydraulic numerical model based on porous media theory was established. A parametric study using single-variable analysis was conducted to investigate the effects of grouting diffusion radius, number of grouting pipes, and freezing pipe shape on the temperature field of the frozen body, the critical seepage velocity, and the final thickness of the freezing wall. The results indicate that: (1)Increasing the grouting diffusion radius results in lower final temperatures at monitoring points and a larger, more uniform freezing wall thickness. However, when the seepage velocity exceeds the critical limit, further increasing the grouting diffusion radius does not enable the freezing wall to fully close. (2)Increasing the number of grouting pipes leads to higher final temperatures upstream and lower final temperatures downstream, reduces seepage velocity, and yields a more uniform and thicker frozen wall. (3)Triangular and square freezing pipes exhibit higher freezing efficiency and produce thicker frozen walls compared to circular pipes. The frozen walls formed with triangular and square cross-sections are also more resistant to erosion under higher flow velocities. The numerical simulation results provide theoretical guidance for selecting construction parameters and support the optimization and evaluation of combined grouting and freezing techniques in engineering practice.