考虑基础-土相互作用的采空区输电铁塔承载特性研究

Bearing capacity of transmission tower in goaf considering foundation-soil interaction

采空区地表沉降后,输电铁塔基础可能发生沉降、倾斜,影响杆件变形及轴力分布,导致杆件失效。以某采空区750 kV输电铁塔为研究对象,建立了输电铁塔、基础与土相互作用的有限元模型,对不同基础型式、不同沉降位置的塔腿杆件轴力分布及变形影响规律进行了分析,同时分析了铁塔基础的受力特性。结果表明,当考虑相互作用影响时,杆件轴力和节点位移随沉降值呈非线性变化;相较于独立基础,不同沉降位置对大板基础的塔腿主材、斜材轴力的影响更大;当基础处于沉降位置时,防护大板能有效减小基础所受应力。

After the land subsidence of the goaf,the foundation of the transmission tower may experience settlement and tilting,which affects the deformation and axial force distribution of the members,leading to member failure.A finite element model of the interaction between the transmission tower,foundation and soil was established using a 750 kV transmission tower located in a goaf as the research object.The axial force distribution of tower leg members with different foundation types and different settling positions is analyzed,the deformation influence rule of transmission tower members in goaf is given,and the mechanical characteristics of tower foundation are analyzed.The results show that when considering the interaction,the axial force and nodal displacement of the member exhibit nonlinear changes with the settlement value.Compared to the independent foundation,different settlement positions have a greater impact on the axial force of main members and diagonal members considering the slab foundation.When the foundation is in the settlement position,the large protective plate can effectively reduce the stress on the foundation.