Numerical study of frost heave behavior in U-elbow of ground heat exchanger

In cold regions, the soil frost heave around the U-elbow can become a key factor in its structural stability. The aim of this study is to develop a numerical model to investigate the frost heave behavior of U-elbow under low temperature (below 0 °C). The numerical model is verified with experimental date. In this study, the frost heave behavior of soil and U-elbow pipe are analyzed. It can be found that the ice content and soil stress show nonuniform distribution around the U-elbow in freezing area. Affected by the unbalanced frost heave action, the U-elbow shows continuous displacement and elliptical deformation.