采动影响下浅埋输气管道与土体耦合作用机理

Coupled Interaction Mechanism Between Shallow-buried Gas Pipelines and Soil During Mining

针对地下煤炭开采对采空沉陷区内浅埋输气管道变形破坏的采动影响,根据采动过程中埋地管道与土体相互作用的基本特征,将采动过程中管土相互作用划分为管土协同变形、管土暗悬空和管道明悬空3个阶段。根据各阶段中埋地管道的力学特征,分别采用弹性地基梁、均布载荷作用下的弹性梁和纵横弯曲弹性梁模型对非沉陷区的管道、沉陷区内处于协同变形的管道和沉陷区内处于悬空状态的管道进行力学分析,建立各阶段下埋地管道的分段弹性梁力学模型;并结合各分段弹性梁的边界条件,分析各阶段下管土相互作用的极限状态,得到埋地管道失效的临界判据,进而建立采动影响下浅埋输气管道与土体作用机理分析方法。

Underground coal mining can potentially induce deformation and destruction of shallow-buried gas pipelines in subsidence areas. Thus, this study analyzed the interactions between a pipeline and soil during mining activities and divided them into three types based on the fundamental characteristics of pipeline soil interaction. These include collaborative pipeline soil deformation, hidden pipeline soil suspension, and apparent pipeline suspension. Depending on the mechanical characteristics of the buried pipeline in each type of interaction, an elastic foundation beam model, uniform loading elastic beam model, and two- way bending elastic beam model were used to analyze the mechanical behaviors of pipelines in a subsidence-free area, pipelines under collaborative deformation in a subsidence area, and pipelines suspended in a subsidence area, respectively. Based on this analysis, a segmented elastic beam mechanical model was developed for buried pipelines of each type. Combining the model with the corresponding boundary conditions, this study further analyzed the ultimate conditions of pipeline soil interaction and the critical criterion for buried pipelines of each type. Finally, an analytical method for investigating the mechanism of interaction between shallow-buried gas pipelines and soil during mining was established.