煤矿采空区猫头型输电铁塔不均匀沉降分析

Analysis of Uneven Settlement of Cat-Head Transmission Towers in Coal Mine Goaf Areas

中文关键词:输电塔-线体系  不均匀沉降  渐进式倒塌  有限元分析

keywords:transmission tower-line system  non-uniform settlement  progressive collapse  finite element analysis

中文摘要:煤矿采空区引发的地表不均匀沉降易导致输电铁塔发生倒塌破坏。为揭示沉降作用下输电塔-线体系的倒塌机理与失稳模式，以某330 kV猫头型输电铁塔为研究对象，采用ANSYS建立考虑几何非线性与渐进失效的三塔四线耦合数值模型，并选取中间铁塔进行分析。结果表明，结构对单支座与三支座沉降极为敏感，当沉降量约0.07～0.08 m时，塔腿斜材发生局部屈曲并引发整体失稳；而在双支座沉降工况下，体系可承受更大的沉降变形，垂直线路方向与顺线路方向的极限沉降量分别约为0.27 m和0.52 m。输电塔-线体系在沉降作用下经历“线性响应-非线性屈曲-残余承载变”3个阶段，其中塔腿斜材的屈曲失稳会引起结构内力路径重分布，并加速全塔倒塌。研究结果识别了不同工况下的沉降预警阈值与失效模式，可为采空区输电铁塔的状态监测与风险评估提供参考。

Abstract:Uneven surface subsidence in coal mining goafs may trigger the collapse and failure of transmission towers. To clarify the collapse mechanism and instability modes of tower-line systems under such circumstances，this study focuses on a 330 kV cat-head type transmission line. A three-tower four-line coupled numerical model，which integrates geometric nonlinearity and progressive failure，is established in ANSYS，with the middle tower designated as the primary research object. The results indicate that the structure show extreme sensitivity to single-support and three-support subsidence. A settlement of approximately 0.07~0.08 m can induce local buckling of the tower-leg diagonal members，thereby leading to overall instability. In contrast，under double-support subsidence，the system demonstrates greater deformation resistance： its ultimate settlement capacities reach approximately 0.27 m in the transverse direction and 0.52 m in the longitudinal direction，respectively. During the subsidence process，the tower-line system undergoes three distinct stages： "linear response，nonlinear buckling，and residual load-bearing change." The buckling instability of the tower-leg diagonal members causes the redistribution of internal force paths，which in turn accelerates the overall collapse of the tower. These findings define the early warning thresholds and failure modes of the system under different working conditions，providing valuable references for the condition monitoring and risk assessment of transmission towers in goaf areas.