Abstract:

The influence of waterice phase transition and seepage velocity on the surrounding rock temperature field distribution during the freezingthawing process of surrounding rock in cold region tunnel is very important. Hence, based on the multiphysics coupling analysis software COMSOL Multiphysics, a coupled model of temperature field with waterice phase transition and seepage field of surrounding rock is established; and the temperature field distribution of surrounding rock in cold region tunnels is analyzed by changing the seepage velocity and the boundary temperature Tm in the freezing and frozen zones. The numerical analysis results show that: (1) The boundary temperature Tm affects the frozen zone range and the time when waterice phase changes at different depths in the surrounding rock, but the different boundary temperature Tm has little influence on the surrounding rock temperature field distribution. (2) The change of seepage velocity has a significant influence on the surrounding rock temperature field distribution when the seepage velocity is higher than 1×10-6 m/s, while the change of seepage velocity affects the surrounding rock temperature field distribution little when the seepage velocity is lower than 1×10-6 m/s. Therefore, the influences of seepage velocity and the waterice phase transition on the surrounding rock temperature field of cold tunnels should be considered in areas with high groundwater seepage velocity.

Key words: cold region tunnels, waterice phase transition, seepage velocity, temperature field, numerical analysis