Stress numerical calculation of pipeline subjected to slope creep in frost area

Long-distance pipeline is buried in the ordinary section, and for the pipeline passing through the seasonal frost area with slope, additional stress is applied due to the slope creep caused by freezing and thawing. The axial stress change of pipeline resulted from the slope creep can be monitored by the axial strain sensors installed along the pipeline. However, for the strength evaluation of pipeline, the initial stress of pipeline strain monitoring should be clear. For the stress detection technology mostly used in laboratory environment is not mature in engineering, the initial stress of pipeline strain monitoring can only be obtained by the calculation method of finite element modeling. Taking the buried section of Sebei-Xining-Lanzhou Pipeline I crossing the seasonal slope frost area as an example, the current major risks of pipeline in the seasonal frost area, distribution and determination of soil displacement, and the stress and deformation of the pipeline in seasonal frost area due to slope creep were introduced. By using the Vector Form Intrinsic Finite Element (VFIFE) method, the numerical simulation of pipeline at hazard point was conducted with space beam element and nonlinear soil spring model, and the stress distribution of the pipeline was obtained, which provides basis for determination of the cross-sectional location of strain monitoring, estimate of current stress distribution and safety assessment of pipeline.