Numerical simulation of soil freezing and associated pipe deformation in ground heat exchangers

In cold regions, the soil freezing always restricts the application of ground source heat pump. The aim of this study is to develop a numerical model to simulate the soil freezing course and investigate the characteristics of soil freezing and associated pipe deformation. Meanwhile, the influence of initial pipes center distance on pipe-soil structure is discussed. It can be found that the ice content and soil compressive stress show asymmetric distributions near the U-pipe. The soil freezing can lead to the pipe deformation and displacement. Smaller initial pipe center distance can lead to more asymmetric and larger soil compressive action on the pipes.