黏性泥石流对山区油气管道的冲击动力响应研究∗

Study on The Impact Dynamic Response of Viscous Debris Flow on Oil and Gas Pipelines in Mountainous Areas

摘要:

近年来，随着人类活动引起的地质灾害和极端天气现象频发，因泥石流引发的管道失效事故及次生灾害不断发生。为掌握黏性泥石流冲击山区油气管道的动力响应规律，建立了基于有限单元法与光滑粒子流体动力学 (FEM?SPH)的山区泥石流与管道的多物理场耦合模型。通过把黏性泥石流浆体简化为非牛顿流体——宾汉流体，研究 X70 钢管在泥石流作用下冲击响应过程，得到了管道不同位置的位移及应力时程特征，结果表明：①将泥石流浆体简化为宾汉流体，并离散为 SPH 颗粒不仅可真实展示泥石流的行进过程，也能清晰地反映泥石流对管道的动力响应规律。②通过建立多物理场耦合模型来模拟黏性泥石流冲击过程，发现泥浆附带的块石将会受到浆体阻力影响，运动加速度将受到限制。③泥石流对管道产生的破坏力主要来自泥石流“龙头”产生的瞬时冲击力和块石造成的局部撞击力；在泥浆作用下，所产生的应力主要分布于管道迎冲面中心截面处和管道背冲面与山体交界处，石块作用力主要集中在撞击部位，对管道背撞面影响较小；泥石流对管道产生的冲击位移整体呈现“马鞍状”的对称分布。研究所采用的非牛顿流体模型为泥石流对建(构)筑物的冲击模拟提供了新途径，相关研究结论可为泥石流段管道的灾害防控提供理论参考。

Abstract:

In recent years， with the frequent occurrence of geological disasters and extreme weather phenomena caused by human activities， pipeline failure accidents and secondary disasters caused by de? bris flow are constantly occurring. In order to grasp the dynamic response law of oil and gas pipelines impacted by viscous debris flow in mountainous areas， a multi-physics field coupling model compris? ing debris flow and pipelines in a mountainous area was established based on finite element method and smooth particle hydrodynamics (FEM-SPH). By simplifying the mud-rock flow slurry to a nonNewtonian fluid—Bingham fluid， the impact response process of the steel pipe X70 under the action of debris flow was studied， and the displacement and stress time history characteristics at different po? sitions of the steel pipe were obtained. The results show the following three points： Firstly， simplify?ing debris flow slurry into Bingham fluid and discretizing it into SPH particles can not only truly show the process of debris flow， but also clearly reflect the dynamic response law of the pipeline to the de? bris flow. Secondly， the impact process of viscous debris flow was simulated by a multi-physical field coupling model， it is found that the acceleration of the rock blocks embedded in the mud is limited by the slurry resistance. And the third point is that the destructive force of the debris flow acting on the pipeline mainly comes from the instantaneous impact force generated by the “fore-end” and the local impact force caused by the rock blocks. Under the action of mud， the stress developed in the pipeline distributes mainly in the central section of the impact face and the interface between the pipeline and rock mass opposite to the impact face. The impact force caused by the rock blocks mainly concentrates on the impact points and has little effect on the back surface of the pipeline. The impact displacement of the pipeline due to the debris flow generally distributes in a symmetrical “saddle shape”. The nonNewtonian fluid model adopted in this study provides a new way to simulate the impact of debris flow on buildings (structures)， and the relevant research conclusions can provide a theoretical reference for the disaster prevention and control of pipeline in debris flow areas.