滑坡作用下埋地管道的弹塑性地基反力解析法

目前关于弹塑性地基中滑坡段埋地管道的解析计算研究较少,计算结果不够精确。为探讨滑坡段埋地管道与土体接触的非线性特征,基于地基反力法,采用简化的弹塑性本构模型来模拟非线性管—土的相互作用,提出了埋地管道与土体相互作用的弹塑性地基反力解析法控制方程组,根据管道变形的连续性条件及边界条件求得管道挠度和内力的解析解,对管道变形和内力进行计算。结合算例进行分析,选取不同参数,探讨了地基反力系数k0对管道变形和内力的影响。研究结果表明：随地基反力系数的增大,管道最大挠度、滑体中部管道弯矩及Mises应力逐渐减小,滑坡周界处管道弯矩及Mises应力逐渐增大；地基反力系数增大,土体对管道约束作用加强,从而引起管道挠度和内力的变化。与Winkler 地基反力法相比,基于弹塑性地基反力法的滑坡作用下管道力学分析理论上更为严谨,有效地提高了计算精度。

Analytical Method of Elastic-Plastic Subgrade Reaction for Buried Pipeline Under the Action of Landslide

The analytical calculations of buried pipeline in the landslide section of elastoplastic soils are relatively few at present. In order to study the nonlinear characteristics of the contact between buried pipeline and the soil in landslide section, based on the subgrade reaction method, the simplified elastic-plastic constitutive relation of the pipeline-soil is adopted to simulate the nonlinear pipeline-soil interaction, a set of governing equations based on the elastic-plastic subgrade reaction method are devised to describe the buried pipeline-soil interaction. Accord-ing to the continuity condition and boundary condition of pipeline deformation, the analytical solutions of the pipeline deflection and internal force are obtained. The reliability of the method is verified by the comparative analysis of the example. The influence of the coefficient of subgrade reaction on pipeline deformation and inter-nal force is discussed by selecting different parameters. The results show that the maximum deflection, the bending moment and Mises stress of the pipeline in the middle of the landslide decrease with the increase of the coefficient of subgrade reaction. The bending moment and Mises stress at the perimeter of landslide increase with the increase of the coefficient of subgrade reaction. The constraint effect of soil on pipeline is strengthened with the increase of the coefficient of subgrade reaction, which causes the change of deflection and internal force of pipeline. Compared with the elastic subgrade reaction method, the proposed method is more rigorous in theory and has higher calculation accuracy.