软土沉降位移作用下大口径管道轴向应力状态研究

Study on longitudinal stress state of large diameter pipeline under effect of soft soil settlement displacement

为准确掌握大口径管道的轴向应力应变状态,保障管道的安全运行,通过假定4类不同形式的软土沉降位移,研究不同沉降形式对管道轴向应力状态的影响。采用非线性有限元方法建立管道轴向应力应变参数化数值计算模型,开展影响因素分析。结果表明:针对软土沉降位移作用下1422 mm X80大口径管道,沉降量相同时,突变型位移载荷作用下管道受到的轴向应力最大,最大轴向应力位于两侧非沉降区距管道中心约53 m处;软土沉降量达到工程实际中可能的最大值1 m时,大口径X80管道内轴向应力小于0.9倍管材屈服强度,管道环焊缝可以采用基于应力的工程适用性评估方法开展ECA(Engineering Critical Assessment)评价。

In order to accurately grasp the axial stress-strain state of large diameter pipelines and ensure the safe operation of pipelines,the influence of different settlement forms on the axial stress state of pipeline was studied through assuming four types of soft soil settlement displacement with different forms.A parametric numerical calculation model of the axial stress-strain of pipeline was established based on the nonlinear finite element method,and the influencing factors were analyzed.The results showed that for the 1422 mm X80 large diameter pipeline under the soft soil settlement displacement,the axial stress of pipeline under the abrupt displacement load was the largest with the same settlement,and the maximum axial stress was located in the non-settlement zone on both sides about 53 m from the center of pipeline.When the settlement of soft soil reached 1m which was the possible maximum value of engineering practice,the axial stress in large diameter X80 pipeline was less than 0.9 times the yield strength of pipe material,and the ECA(Engineering Critical Assessment)evaluation can be carried out on the pipeline girth welds by applying the engineering suitability evaluation method based on stress.