The artificial freezing method is commonly used in tunneling beneath overlying structures due to the significant development and utilization of underground space. However

there is a growing demand for controlling frost heave deformation in overlying structures and the interaction laws of these structures during freezing and undercutting remain unclear. Hence

a multi-physics coupling deformation calculation method is proposed. This study focuses on the shield tunneling project of Shanghai Metro Line 18 at Guoquan Road Station

which intersects with the existing upper operating station of Line 10. It investigates the construction approach for new tunnels during freezing

using the gray clay of layer ⑤1 in Shanghai as the research target

particularly examining the disruptive effects on the primary structures of the upper operating station. Considering water migration

we derived the frost heave deformation formula and developed an improved thermo-hydro-mechanical coupling theory model by using pore ratio

freezing temperature

and average water pressure as coupling variables. Through frost heave tests on cohesive soil

we obtained the stress-strain relationship of frost heave specimens to describe the changes in pore structure. Subsequently

a thermo-hydro-mechanical three-field coupling numerical calculation was conducted using the weak form module (PDE) of COMSOL Multiphysics software. The simulation results closely matched the monitoring data and were below the predetermined control value

validating the accuracy of the enhanced coupling theory. These findings offer a multi-physics coupling approach for calculating deformations in similar frozen underpass tunnels

serving as a valuable reference for freezing method design and construction parameters. Additionally

we propose safety control indicators for reinforcement construction based on this scientific groundwork.