截断阀室水淹后管道沉降的防护技术研究

为了保证长输天然气管道的安全运行，需要对其截断阀室遭受水淹后管道的不均匀沉降行为进行研究。应用ANSYS软件建立了管土非线性接触模型，通过对其进行分析建立了沉降量与最大Von Mises应力和椭圆度之间的映射关系，结果表明:不均匀沉降对管道强度的影响更明显，二者间基本呈线性关系，最大Von Mises应力随着沉降量的增大而增大，根据第四强度理论便可确定管道失效时的极限沉降量。同时还探讨了管径、内压、壁厚、埋深对管道应力状态的影响，降低内压、增大壁厚以及减小埋深和管径均可降低不均匀沉降时管道的最大Von Mises应力，但其中管径和壁厚的变化对管道最大Von Mises应力的影响更为显著。预期研究结果可以为山区管道的实时监测与防护措施制定提供一定的技术支持。

Study on protection technology of pipeline settlement in flooded block valve station

It is necessary to study the differential settlement behavior of pipeline in flooded block valve station in order to protect the safe operation of long-distance gas pipeline. The nonlinear contact model of pipe and soil was built by using ANSYS. By analyzing the model, the mapping relationship of the settlement with the maximum Von Mises stress and ovality was set up. It showed that the differential settlement had more effect on the pipeline strength, and the linear relation was presented between them. The maximum Von Mises stress increased with the increase of settlement, and the ultimate settlement in pipeline failure can be determined according to the fourth strength theory. Meanwhile, the influence of diameter, pressure, wall thickness and burial depth on the stress status of pipeline were also studied. Reducing pressure, increasing wall thickness and decreasing burial depth and diameter can reduce the maximum Von Mises stress of pipeline with differential settlement. Among them, the change of diameter and wall thickness had more effect to the maximum Von Mises stress. The proposed result can provide a certain technical support for real-time monitoring and making protection measures on pipelines in mountainous area.