Multiphysics coupling study on pipeline deviation in the freezing method for submarine tunnel pipe curtains

In submarine tunnel construction, displacement of the freezing pipes may occur. Combined with the effects of groundwater seepage, this can compromise the integrity and waterproofing performance of the frozen soil curtain. Taking the pipe curtain freezing project of the submarine tunnel in the Sanya estuary channel as an example, two typical types of pipeline offsets are focused on. “Layout 1” refers to the outward offset of all pipelines, while “Layout 2” refers to the offset of local pipelines. Research has found that when there is no groundwater flow, layout 1 has the highest risk. Layout 2 has the highest risk under x-direction seepage. However, the y-direction seepage causes the difference in risk between the two types of offsets to not be significant. At the same time, the relationship between pipeline offset, groundwater flow, and freezing effect was studied and analyzed, and a multiphysics coupled correlation model was established. Finally, a method of “local encryption” was proposed, which involves adding frozen pipes to the most risky scheme. This provides a reference for controlling the risk of frozen pipe deviation in similar projects in the future.