管土耦合作用下长输直埋管道沉降分析

Analysis on the Settlement of Long Distance Direct-buried Pipelines under Pipe-Soil Coupling Effect

为保障管道输送的安全运行,对长输直埋管道的沉降问题展开研究。考虑直埋管道周边土体特征的影响,分析管-土之间的相互作用关系,建立了基于Drucker-Prager弹塑性准则的管土相互作用模型。应用有限单元法建立管土接触三维有限元模型,管道与周边土体采用三维实体单元进行离散,管土相互作用面采用非线性接触单元进行模拟。以某直埋管道为例,分别对管土同步沉降初期和管道局部悬空沉降进行了数值模拟和分析,悬空沉降分析中考虑了管-土初始应力和初始位移的影响,得到管道在不同沉降阶段的应力结果和力学特征;通过模拟不同土体弹性模量,得到了敷设土体特征对管道变形的影响规律。直埋管道有限元模型的建立可实现对长输直埋管道沉降变形研究,为管道的安全性分析提供了参考。

In order to ensure the safe operation of pipeline transportation,the settlement problem of long distance direct-buried pipeline is studied. By considering the influence of surrounding soil characteristics and analyzing the pipe-soil interaction, the pipe-soil interaction model based on DruckerPrager elastic-plastic criterion is established. By the finite element method,the three-dimensional finite element model of pipe-soil contact is established,the pipeline and its surrounding soil are separated by three-dimensional entity units, and the interface of pipe-soil is simulated by nonlinear contact units. Taking a direct-buried pipeline as an example,the initial synchronous settlement of pipe-soil and local suspension settlement of pipelines are simulated and analyzed. In the analysis of suspension settlement,the initial stress and initial displacement are considered,and the stress results and mechanics characteristics of pipelines in different settlement stages can be achieved,and the influence law of laying soil characteristics on pipeline deformation can be obtained. The establishment of the finite element model for direct-buried pipelines realizes the study of settlement deformation of long distance directburied pipelines,and provides reference opinions for safety analysis of pipelines.