Mechanical analysis of frost heaving of pipeline in gas offtake station

The soil freezing around gas offtake pipeline at negative temperature may cause frost heaving and deformation of pipeline under frost heaving loading. When the pipeline is raised, the maximum bending moment, initial point of stress and pipeline safety can be determined by analyzing the distribution laws of force and displacement of pipeline caused by soil frost heaving. The control factors of lifting force caused by soil frost heaving are analyzed. The calculation models of pipeline internal force and displacement caused by soil frost heaving are esta blished based on the calculation model of pipeline lifting force by frost heaving and pipe-beam equation. The above model's rationality is proved by the Nixon experiment data. The data from Zhengzhou Gas Company, user of Zhengzhou Gas Offtake Station in West-to-East Gas Pipeline, is analyzed and calculated by this model. Results show that the operation of pipeline is in a safe situation when the lifting height of pipeline is at 30 mm, that is, the non-uniform frost heaving capacity around the adjacent soil of pipeline is at 60 mm.