融沉位移作用下X65管道的应变响应

Strain response analysis of X65 steel pipeline under thawing settlement

冻胀融沉引起的土壤位移会对埋地管道的结构安全造成重大威胁。基于非线性有限元程序ABAQUS,采用INP编程语言建立融沉位移作用下管道应力应变响应的参数化数值求解模型,并试验验证了模型的准确性。通过影响因素分析,探究了管道的应变分布特性。结果表明:对于穿越多冰冻土区的X65管道,在融沉区宽度较小的情况下,管道内最大轴向应变位于融沉区中心,管道拉应变大于压应变,整体受拉;当融沉宽度大于60 m时,管道随地表一同融沉,管道最大应变体现为弯曲应变,最大应变位于融沉区边缘,融沉区宽度增加不会对管道应变产生明显影响。因此,在冻土融沉区地灾监测中应重点识别融沉区范围,对于小范围融沉,需要对融沉区中心和边缘应变状态加以监控;对于60 m以上融沉区,则需要对融沉区边缘加以监控。

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 X65pipeline 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.(9 Figures, 23 References)