Strain response analysis of X65 steel pipeline under thawing settlement

Abstract

Soil displacement caused by frost heave and thawing settlement will pose a great threat to the structural safety of buried pipelines. Herein, a numerical solution model for parameterization of pipeline stress-strain response under the action of displacement caused by thawing settlement was established with the nonlinear finite element program ABAQUS and the INP programming language. The accuracy of model was verified with the test results. Meanwhile, the distribution characteristics of pipeline strain were studied through the analysis of influencing factors. The results show that: for X65 pipeline passing through the ice-rich permafrost area where the thawing settlement area is in small width, the maximum axial strain is located in the center of the thawing settlement area, and the tensile strain of the pipeline is greater than the compressive strain, so that the entire pipeline is in the state of tension. However, when the thawing settlement area is wider than 60 m, the pipeline is subjected to thawing settlement together with the ground, with bending strain as the maximum strain, which is located at the edge of the thawing settlement area. Besides, the widening of thawing settlement area will not affect the pipeline strain significantly. Therefore, attention should be paid to the identification of the range of thawing settlement areas in the geohazard monitoring. Generally, for the thawing settlement areas with small width, pipeline strain in the center and edge of thawing settlement areas should be monitored, while for those thawing settlement areas with width larger than 60 m, the pipeline strain at the edge of thawing settlement areas should be monitored.

Keywords

• x65 pipeline
• thawing settlement of frozen soil
• pipe-soil coupling
• mechanical analysis
• strain analysis