基于柔性石墨防腐蚀材料的杆塔桩基紧凑型接地研究

Research on Compact Grounding of Tower Foundation Based on Flexible Graphite Anticorrosive Material

架空输电线路杆塔接地施工往往受耕地征用、青苗补偿、道路建筑阻断、线路走廊限宽等条件制约,提高杆塔桩基自然接地的散流能力对降低接地电阻和节约施工成本具有实际意义。用柔性石墨防腐蚀材料的杆塔桩基紧凑型接地方法,采用有限元软件COMSOL Multiphysics建立杆塔桩基散流计算模型,针对单桩基、双桩基及全塔四桩基外敷方式的接地特性与影响因素进行仿真,分析了引流线位置对外敷电极分流特性的影响规律。计算结果表明:对于单个混凝土桩基,引流线位置对接地电阻以及桩基散流特性影响较小;当杆塔采用双基坑和大开挖单基坑施工时,逐桩分体外敷和一体外敷均能起到降阻效果。综合考虑施工难度、材料用量以及外敷方式的通用性,实际杆塔在施工时宜选择逐桩分体外敷方式。

The grounding construction of overhead transmission line towers is restricted by the conditions of compensation for cultivated land requisition,compensation for young crops,road building blockage,and widening of line corridors.It is of practical significance to improve the dispersive capacity of natural grounding of the tower foundation to reduce the grounding resistance and save construction cost.In this paper,the compact grounding strategy of tower foundation based on flexible graphite anticorrosive material was proposed.The finite element software COMSOL Multiphysics was used to establish the dispersion calculation model of the tower foundation.The grounding characteristics and influencing factors of the single tower foundation,double tower foundation and the whole four tower foundation external application method were simulated.The influence of the position of the drainage line on the characteristics of the external electrode shunt was analyzed.The calculation results showed that for the single-base concrete pile foundation,the position of the drainage line had little effect on the grounding resistance and the characteristics of the tower foundation.When the tower adopted the double foundation pit and large excavation single foundation pit,both of the external application of pile by pile and integral external application played a grounding resistance reduction effect.Considering the difficulty of construction,the amount of materials and the universality of external application,pile by pile separate external application was selected for practical tower construction.