水平二层土壤中矩形复合地网基础接地电位研究

用矩量法,对埋在水平分层的二层土壤中的矩形混凝土内含有水平以及竖直钢筋的复合接地网,在地面所产生的电位进行了研究,得出计算公式,用FORTRAN语言编制了计算程序,用MATLAB软件绘制出电位分布图.由图看出,混凝土以及土壤的电阻率对地面电位分布影响较大,当混凝土电阻率远大于土壤电阻率时,地面地位分布与没有混凝土的地网相近,此时,地面电位在钢筋外部边角附近下降较快,跨步电压在此处形成一个峰值;当混凝土电阻率远小于土壤电阻率时,地面电位则在混凝土的外部边角附近下降较快,跨步电压在此处形成一个峰值;当混凝土电阻率与外部土壤电阻率相差不是很大时,跨步电压则在钢筋外部边角附近以及混凝土的外部边角附近各形成一个峰值.从安全接地来看,利用基础接地时,应对这2处跨步电压可能出现峰值的地方都加强安全措施.

A Study on the Electric Potential on the Ground of the Foundation Grounding System in Rectangular Concrete with Combined Grounding Grid Surrounded by Two-layer Earth

By Moment Method,the systematic grounding electric potential of the rectangular concrete grounding grid,buried in two-layer soil,with the horizontal and vertical reinforcing bars,has been calculated and a formula achieved.A computation program is worked out with PORTRAN language and a potential distribution map is drawn with the MATLAB software.Shown by the figures,the electrical resistivity of the concrete and the soil are greatly related to the potential distribution on the ground.When the electric resistivity of the concrete is greater than that of the soil,the electric potential distribution on the ground is close to the grounding grid without a concrete,and the electrical potential on the ground reduces quickly near the outer corner angle of the reinforcing bars,where the step voltage forms a peak.When the electric resistivity of the concrete is less than that of the soil,the potential on the ground reduces quickly near the outer corner angle of the reinforcing bars,the step voltage produces a peak.When the electric resistivity of the concrete doesn't differ greatly from that of the soil,the step voltage produces two peaks near the corner angle of the reinforcing bars and corner angle of the concrete respectively.In terms of safety grounding,the safety measures should be taken near the places where two peaks may be produced when foundation grounding is applied.