埋地管道极限悬空长度研究

发布时间：2018-07-08 14:35

本文选题：埋地管道 + 悬空长度　；参考：《西安石油大学》2015年硕士论文

【摘要】：长输管道沿线地质地貌错综复杂,自然条件恶劣,容易受外界载荷(如地质滑坡、坍塌、疏松土体沉降、湿陷性黄土、地震、水毁等)影响导致大跨度悬空,给管道的安全运行带来严重隐患。因此,对悬空管道的研究十分有必要。本文首先利于土体的基本性质和本构方程,分析了埋地管道意外悬空时,可能存在的载荷情况;基于Winkler假设的弹性地基梁理论建立了管道两端埋地段管土作用的悬空管道模型,分析了悬空管道跨中截面和管道内出土端的弯矩和挠度。其次,在应力失效准则范围内,基于Mises屈服理论确定出管道悬空长度判断依据。最后,利用土体的摩尔库伦模型和管线钢材料的Ramberg-Osgood本构方程,采用有限元软件ABAQUS建立了悬空管道的结构静力学分析有限元计算模型。计算分析得出如下结论:(1)悬空管道上最大应力、最大应变出现在悬空管道的内出土端的上表面,最大位移出现在悬空管道跨中截面,而此处应力较小;最大应力、最大应变和最大位移都随着悬空长度的增加而变大;当悬空管道处于弹性阶段时,管道上最大应力对悬空长度的变化敏感;当悬空管道出现局部屈服时,最大应变对悬空长度的增加比较敏感;(2)在悬空管道的内出端截面上,管道上的Mises等效应力,从上轮廓线到下轮廓线先减小后增大,在上轮廓线处最大。在悬空管道的跨中截面上,管道上的Mises等效应力,从上轮廓线到下轮廓线也是先减小后增大,在下轮廓线处最大;(3)对于管道材料为X60、规格为Φ508×7.4mm、土体介质为粘土、内压为4.3MPa、埋深为2m的输气管道,当悬空长度为93m,最大Mises应力达到管道材料的许用应力。当悬空悬空长度为180m;最大Mises应力达到管道材料的屈服强度。同等条件下,埋地输油管道悬空长度为50m,达到许用应力;悬空长度为73m,达到屈服强度;(4)对于以管道内压为单变量的输气悬空管道,随着内压增加,悬空长度降低;对于以管道壁厚为单变量的输气悬空管道,壁厚增加悬空长度增加;通过本文得到的结果对评价实际的悬空管道有着指导作用,并为管道的维修作业提供直接的理论数据支持。
[Abstract]:The geological and geomorphology along the long distance pipeline is complicated, and the natural conditions are bad, which are easy to be affected by the external loads (such as geological landslide, collapse, loose soil subsidence, collapsible loess, earthquake, water destruction, etc.), resulting in the suspension of large span. It brings serious hidden trouble to the safe operation of pipeline. Therefore, it is necessary to study the suspended pipeline. In this paper, the basic properties of soil and constitutive equation are analyzed firstly, and the potential loads of buried pipeline are analyzed, based on Winkler's assumption of elastic foundation beam theory, the suspended pipe model of pipe and soil action at both ends of pipeline is established. The bending moment and deflection of the suspended pipe span and the unearthed end of the pipe are analyzed. Secondly, in the range of stress failure criterion, based on Mises yield theory, the judgment basis of pipeline suspension length is obtained. Finally, the finite element model for structural statics analysis of suspended pipeline is established by using the Moore Coulomb model of soil and the Ramberg-Osgood constitutive equation of pipeline steel material, using the finite element software Abaqus. The results of calculation and analysis are as follows: (1) the maximum stress and strain appear on the upper surface of the inner unearthed end of the suspended pipe, and the maximum displacement occurs in the middle section of the span of the suspended pipe, where the stress is small; the maximum stress, The maximum strain and displacement increase with the increase of the suspended length, the maximum stress is sensitive to the variation of the suspended length when the suspended pipeline is in the elastic stage, and the local yield of the suspended pipeline is observed. The maximum strain is sensitive to the increase of the suspended length. (2) the Mises equivalent stress on the inner and outer end of the suspended pipe decreases first from the upper contour to the lower contour and then increases, and the maximum is at the upper contour. The Mises equivalent stress on the span of the suspended pipeline decreases first and then increases from the upper contour to the lower contour, and the maximum is at the bottom contour. (3) for the pipeline material X60, the specification is 桅 508 脳 7.4 mm, the soil medium is clay. When the suspended length is 93 m, the maximum Mises stress is equal to the allowable stress of pipeline material when the internal pressure is 4.3 MPA and the buried depth is 2 m. When the suspension length is 180 m, the maximum Mises stress reaches the yield strength of the pipe material. Under the same conditions, the suspended length of buried oil pipeline is 50m, the allowable stress is achieved, the suspended length is 73m, and the yield strength is achieved. (4) for the gas pipeline with internal pressure as a single variable, the suspended length decreases with the increase of internal pressure. For the pipeline with single variable wall thickness, the length of the suspended pipe increases with the increase of the wall thickness, and the results obtained in this paper have a guiding role in evaluating the actual suspended pipeline and provide direct theoretical data support for the maintenance of the pipeline.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE973

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