输电线路杆塔桩基钢筋散流及其优化技术

Steel bar flow and optimization technology in power pole pile foundation

输电线路杆塔桩基是杆塔接地的重要组成部分,提出在混凝土桩基回填之前采用柔性石墨接地体绕包桩基的接地优化措施。为研究柔性石墨接地体绕包方式对电力杆塔桩基内钢筋散流和接地电阻的影响,在COMSOL Multiphysics中建立不同绕包覆盖面积和间距的桩基散流三维计算模型,分别计算桩基内钢筋散流、外层绕包接地体的散流、杆塔基础接地电阻以及桩基附近对地电位的影响。计算结果表明:在土壤电阻率高的地区,单独依靠杆塔桩基自然接地难以符合杆塔接地设计要求,采用柔性石墨接地体绕包桩基能起到明显的辅助散流和地表均压作用,杆塔桩基自然接地的降阻效率与土壤条件有关。仿真计算相关结论可为输电线路杆塔接地设计与降阻改造提供参考。

The transmission tower pile foundation plays an important role in the tower grounding system.This paper proposes a grounding optimization measure of flexible graphite grounding body wrapped pile foundation before the concrete pile foundation backfilling.In order to study the influence of the flexible graphite grounding body wrapping method on the steel bar flow and grounding resistance in the power pole tower pile foundation,a three-dimensional calculation model of pile foundation flow is established in COMSOL Multiphysics with different wrapping coverage area and different winding spacing.The dispersion of steel bars in the pile foundation,the dispersion of the outer layer around the grounding body,the grounding resistance of the tower foundation and the influence of the pile foundation on the ground potential are calculated respectively.The calculation results show that in the area with high soil resistivity,the natural grounding of the pile foundation alone is difficult to meet the requirements of the tower grounding design.After the flexible graphite grounding body is wrapped around the pile foundation,it can play an auxiliary flow and surface pressure equalization.The resistance reduction efficiency of the natural grounding of the pile foundation is related to the soil conditions.The relevant conclusions of simulation calculation in this paper can provide reference for grounding design and resistance reduction of transmission line tower.