Collapse mechanism and protection of buried pipelines in frozen soil area under hydro-thermal-mechanical coupling analysis

The collapse mechanism of buried pipelines in frozen soil areas is explored to protect buried pipelines. The classical hydrodynamic model and the basic theory of thermoelasticity are used to construct a hydro-thermal-mechanical coupling mathematical model suitable for frozen soil. It can be divided into two steps: the full coupling of water and heat and the one-way coupling of water, heat and force. The geometric model is established and the network is divided. The analyzed hydrothermal results are imported into the model. The frost heave deformation of the buried pipeline surface in the frozen soil area is simulated and analyzed. The collapse mechanism of buried pipelines in frozen soil areas is combined and studied. The vertical stress of the buried pipeline increases with the increase of the relative stiffness of the pipe soil. The research shows that the larger the diameter of the buried pipeline is in the frozen soil area, the easier it is to collapse and the greater the displacement of the buried pipeline is. Moreover, the vertical stress on the pipeline increases with the increase of the pipe diameter.