采煤沉陷区输电铁塔复合防护板基础抗变形性能及其板厚取值研究

Research on the Composite Foundation Anti-deformation Performance and Optimal Thickness of Electricity Transmission Towers in Mining Subsidence Area

以某采煤沉陷区内的典型输电铁塔及其复合防护板基础工程为背景,考虑地基-基础-上部铁塔结构的共同作用,对不同板厚复合防护板基础的抗采动变形性能进行了研究,并引入"保护作用"的概念,对独立基础和复合防护板基础的抗变形性能进行了分析。研究表明,设置复合防护板后,与独立基础相比,可明显减少铁塔支座的水平位移及上部结构的应力,支座位移与结构应力随着复合大板厚度的增大而减小,其减小的幅度随着板厚的增大而趋缓,当板厚达到一定数值以后几乎不再减小。提出的复合防护板的厚度可取铁塔基础长向根开的1/45～1/35的建议,以供采煤沉陷区内复合防护板基础的设计参考。

In this paper,the finite element models are established for typical kinds of electricity transmission tower.The anti-deformation performances of single foundation and composite foundation with different thickness protection plate are studied with numerical simulation.The study indicates that,compared to the single foundation,the horizontal displacements of supports and the stresses of the upper structure are distinctly decreased by the composite foundation.The study also indicates that,the improvement of anti-deformation performance by increasing thickness of protection plate played an important role only in a limited range,the feasible minimum thickness of the plate is about 1/45-1/35 of the distance between two supports.As a result,the study lends a support to the improvement of the foundation design method for the transmission tower in the subsidence area.