Mechanical Response Analysis and Safety Assessment of Shallow-Buried Pipeline under the Influence of Mining

摘要

In accordance with the influence of underground mining on the deformation and failure of a shallow-buried gas pipeline, the pipe-soil interaction during mining is classified into two stages, namely coordinated deformation stage and partial hanging stage. According to the mechanical characteristics of the buried pipeline in each stage, the models of a) a beam on an elastic foundation, b) an elastic beam under uniform load, and c) a vertical and horizontal bending beam are introduced in a mining subsidence zone to mechanically analyze, respectively a) the pipeline in non-mining subsidence zone, b) the pipeline at the coordinated deformation stage, and c) the hanging stage. Mechanical model of segmented elastic beam of shallow-buried pipeline is established for each stage. Combined with the boundary conditions of each segmented elastic beam, the limiting condition of the pipe-soil interaction under the two stages is analyzed, and thus, the critical criterion of shallow-buried pipeline failure is obtained. Consequently, the mechanical analysis method on the deformation and failure of the shallow-buried pipeline is obtained. This method is used to analyze the practice of coal mining under a pipeline in Shanxi province, China. The analysis shows that the pipeline will likely fail in the pipe-soil partial hanging stage. Therefore, the pipe-soil interaction should be controlled within the coordinated deformation stage, in which the safe maximum length of working face should be limited to 435 m.