采空区输气管道沉降数值模拟

Numerical simulation of gas pipeline settlement in mined-out area

针对埋地输气管道因采空沉陷带来的安全问题,以实际地质参数为基础,基于ABAQUS有限元软件建立采空区埋地管道三维模型,研究不同采空区域宽度下,管道走向与开采走向水平夹角、内压、壁厚和管沟对管道von Mises应力的影响。结果表明:管道内压对埋地管道力学性能的影响较为显著,管道最大von Mises应力随管道内压的增加近似地线性增大;增大管道壁厚可以有效减小管道应力,对于危险管段可以通过替换壁厚较大的管道来提高管道安全性;随着采空区域宽度的增大,管沟对于降低管道最大von Mises应力效果越明显,当采空区域宽度为300 m时,管道最大von Mises应力由449.27 MPa减小到325.63 MPa,缩减了27.52%。考虑到实际工程的经济性和可行性,建议采用管沟回填的方式来提高该地区采空区管道的安全性。

Aiming at the safety problem of a buried gas pipeline caused by mined-out area subsidence, a three-dimensional model of the buried pipeline in mined-out area was established based on the actual geological parameters and the finite element software ABAQUS. The effects of internal pressure, horizontal angle between pipeline strike and mining strike, wall thickness and trench lay out on the maximum von Mises stress of the pipeline were studied under different widths of the mined-out area. The results show that the internal pressure of the pipeline has a significant impact on the mechanical properties of the buried pipeline, and the maximum von Mises stress of the pipeline increases linearly with the increase of the internal pressure of the pipeline;with the increase of wall thickness, the maximum von Mises stress on the pipeline decrease obviously, therefore, the pipeline with larger wall thickness can be used in the dangerous area of mined-out area to improve safety;with the increase of the width of mined-out area, the effect of trench laying on reducing the maximum von Mises stress is more obvious, when the width of the mined-out area is 300 m, the maximum von Mises stress on pipeline decreases from 449.27 MPa to 325.63 MPa, which is reduced by 27.52%. Taking the economy and feasibility of the project into account, it is suggested to adopt the way of trench laying to improve the safety of pipeline in the mined-out area.