基于壳单元的连续型采空区埋地管道应变分析

Strain analysis of buried pipelines in continuous mining subsidence areas based on shell element

采空沉陷区管道在地表变形的作用下会产生较大的应变,导致管道拉裂或屈曲失效,因而建立了三维连续型位移采空区管道应变数值计算模型,该模型使用非线性壳单元模拟管道,非线性弹簧模拟管土间相互作用。基于有限元模型,分析了管道应变空间分布特征及其随主要影响因素的变化规律。结果表明:连续型采空沉陷作用下管道会产生与地表一致的垂向位移,管道内弯曲应变远小于轴向应变;采空沉陷区管道的轴向应变随着覆岩岩性硬度的增强而增加,随着走向长度、开采深度的增加而增加,而煤层采厚对轴向应变几乎没有影响;管道内压、管道埋深、管土间摩擦折减因数的增加均会导致管道轴向应变的增大,增加管道壁厚能够有效减小管道的轴向应变。

Under the action of deformation, the pipeline in mining subsidence areas will produce large strain, which causes the failure of the pipeline to crack or buckling. In this paper, a 3D numerical computation model was established for study the strain of pipeline in continuous-displacement mining subsidence areas. In this model, the pipeline is simulated by the nonlinear shell element and the interaction between pipe and soil is simulated by non-linear spring element. Then, the spatial distribution characteristics of pipeline strain and its relationships with the main influential factors were analyzed on the basis of the finite element model. It is shown that when the pipeline is subjected to continuous mining subsidence, its vertical displacement is consistent with that of ground deformation, and the bending strain inside the pipeline is much smaller than the axial stain. The axial strain of the pipeline in the mining subsidence area increases with the increase of overlying strata stiffness, strike length and mining depth. The effect of the mining thickness on the axial strain is negligible. The axial strain of pipeline is increased as pipeline operating pressure, buried depth and coefficient of pipe-soil friction reduction increase, and it can be reduced effectively by increasing the wall thickness of pipeline. （12 Figures, 1 Table, 20 References）