高陡边坡输气管道的受力特性分析

为了探究高陡边坡对输气管道安全性的影响,应用ANSYS有限元软件,考虑管道和土体之间相互作用的非线性,建立了高陡边坡处管土相互作用的三维有限元模型,分析了设计工况下管道的应力状态。通过计算发现,高陡边坡处管道的应力集中和最大纵向位移主要出现在下坡段弯管处,管道承受的最大Von Mises应力为189 MPa,最大纵向位移为3.79 mm,椭圆度为1.23%,均满足规范要求,高陡边坡处管道的通行方案可行。为了确定合理的管道通行方案,分析了坡高、管径、内压和壁厚对管道应力和变形的影响,分析结果表明:当坡高大于15 m时,应采取增加支墩、采用阶梯式下坡等方式,以减小重力载荷对下坡段弯管的直接作用;大口径管道更容易发生强度和稳定性失效破坏;当内压达到7.5 MPa时,管道将发生强度失效,但未发生稳定性失效;随着壁厚增加,管道的应力和椭圆度均有所下降,但下降幅度并不大。研究结果可以为山区管道的设计和安全防护提供一定的技术支撑。

Mechanical Behavior Analysis of Gas Pipeline in High and Steep Slope

To study the impact of high and steep slope on the safety of gas pipeline,ANSYS finite element software is used to establish a three-dimensional finite element model of gas pipe and soil at high and steep slope considering the nonlinearity of the interaction between the pipeline and the soil.The stress state of the pipeline under design conditions is analyzed.Through calculation,it is found that the stress concentration and maximum longitudinal displacement of the pipeline in the high and steep slope mainly appear at the bend pipe in the downhill section.The maximum Von Mises stress of the pipeline is 189 MPa,the maximum longitudinal displacement is 3.79 mm,and the ellipticity is 1.23%,which meets the requirements and provides a feasible pipeline layout scheme in high and steep slope.To determine a reasonable pipeline layout plan,the impact of slope height,pipe diameter,internal pressure and wall thickness on pipeline stress and deformation is analyzed.The results show that when the slope height is larger than 15 m,additional buttress and step-down slope should be adopted to reduce the direct effect of gravity load on the bent pipe in the downhill section.Large-diameter pipelines are more prone to strength and stability failure.When the internal pressure reaches 7.5 MPa,the pipeline will experience strength failure,but no stability failure.With the increase of wall thickness,the stress and ovality of the pipeline decreases considerably.The study can provide some technical support for the design and safety protection of pipeline in mountain area.