基于管沟尺寸的冻胀作用下输油管道应力分析

Stress Analysis of Oil Pipeline under Frost Heave Based on the Size of the Pipe Trench

冻土区土壤因其特殊性易受温度影响,土壤冻胀会使敷设在管沟内的管道翘曲变形。为使有限元分析结果更符合管道敷设在一定管沟尺寸下的实际要求,利用ABAQUS软件建立基于管沟参数的有限元模型,在冻胀作用下分析了管道在不同管沟尺寸参数下的应力分布规律。对比分析了在不同地表温度、管沟坡度、沟底加宽裕量等情况下的管道应力集中现象以及各参数对管道应力峰值的影响。结果表明:管道在冻胀区域与过渡区和非冻胀区会出现应力集中现象,管底冻胀区域中部为高风险失效区,地表温度对管道轴向应力分布影响最显著。管顶最大Von Mises应力在冻胀区域中部且随管沟坡度的增大而增大,过渡区和非冻胀区交界处的最大Von Mises应力随管沟坡度的增大而减小。管沟坡度一定时,过渡区和非冻胀区交界处的Von Mises应力最大,且随沟底加宽裕量的增大而增大。

The soil in the frozen soil area is susceptible to temperature due to its particularity,and the frost heave of the soil warps and deforms the pipelines laid in the trenches.In order to make the finite element analysis results more in line with the requirements of pipeline laying under a certain trench size,the ABAQUS software was used to establish a pipe-soil interaction model based on trench parameters,and the stress distribution law of the pipe under different trench size parameters was analyzed under the effect of frost heave.The pipe stress concentration phenomenon and the influence of various parameters on the peak stress of the pipe under the conditions of different surface temperature,pipe trench slope and widening margin at the bottom of the trench were compared and analyzed.The results show that stress concentration occurs in pipelines in the frost heave area,transition zone and non-frost heave area.The middle of the frost heave area at the bottom of the pipe is a high-risk failure area,and the surface temperature has the most significant impact on the pipeline stress.The maximum Von Mises stress in the middle of the frost heave area on the top of the pipe increases with the increase of the trench slope,the maximum Von Mises stress in the transition zone and the non-frost heave zone decreases with the increase of the pipe trench slope.When the slope of the pipe trench is constant,the Von Mises stress at the junction of the transition zone and the non-frost heave zone is the largest,and it increases with the increase of the width of the trench bottom.