穿越正断层埋地管线的破坏模式分析

Analysis of the failure modes for continuous buried pipeline crossing the normal fault region

在正断层引起的地面永久性大变形作用下,埋地管线可能会发生拉伸、剪切等形式的强度破坏,亦可能在局部受压区发生屈曲破坏。利用ABAQUS有限元分析软件,建立穿越正断层埋地管线的空间有限元分析模型,采用非线性接触分析方法模拟正断层引起的地表永久性大变形作用下管线—土体间的相互作用,分析了不同管径、跨越角对管线破坏模式的影响。依据算例分析可知:小口径埋地管线易发生拉伸强度破坏,大口径薄壁管线易发生屈曲失效,口径0.65m是管线从发生强度破坏到发生屈曲破坏的临界值;当跨越角大于90°时,角度越大越易发生屈曲失效,跨越角为100°是埋地管线发生强度破坏与屈曲失效的分界点。

Tensile,shear strength and other forms of damages,even buckling failure in local compression zones will happen to buried pipelines under the action of ground permanent large deformation caused by normal fault movement.We used ABAQUS software to establish a three-dimensional pipe-soil interaction model under the ground permanent deformation,adopted nonlinear contact method to simulate the pipelinesoil interaction,and analyzed the influence of different pipe-diameters and crossing angles on the failure mode.By analyzing some examples,it is showed that tensile strength damage is prone to happen to smalldiameter pipelines,while buckling failure to thin-wall large-diameter pipelines,and the critical value of pipe-diameter from intensity damage to buckling failure is 0.65 m.When crossing angle is bigger than 90°,the bigger the angle is,the easier buckling failure happens.And the critical value of crossing angle from intensity damage to buckling failure is 100°.