摘要
采用直流电法进行室内试验和现场的数值模拟时,由于边界条件和现场不同,会造成电场分布与现场存在一定的偏差.本文为了减小边界影响,在一定的电位相对偏差(实验值或数值解与半无限理论解)水平下,优化室内试验和现场数值模拟的模型尺寸,对两个异性点电流源均匀介质电场进行数值模拟,得出以下主要结论:在模型顶面供电电极之间电位的最大相对偏差小于1%的前提下,直流电法现场的数值模拟(零电位边界)采用长方体模型(长和宽相等),模型的高取为供电电极极距的1.75倍,模型的宽取为4.35倍时,在一定精度上模型的体积较小;直流电法室内试验(绝缘边界)采用长方体模型(长和宽相等),模型的高取为供电电极极距的3倍,模型的宽取为4.35倍时,在一定精度上模型的体积较小.当模型边界取为零电位边界时,在相同的供电电极极距下,模型顶面供电电极之间电位达到相同的相对偏差水平时,半球形模型的体积比长方体模型的体积更小.这些结论对数值模拟反演现场情况以及进行室内试验时模型的设计有一定的指导意义,使得相关规律能较好的应用于现场.
The indoor test and numerical simulation of the direct current method could cause a certain deviation of the electric field distribution compared to the field because the boundary conditions are different from the field.In this paper,in order to optimize model size of indoor test and field numerical simulation at a certain level of relative potential deviation(experimental or numerical solutions and theoretical solutions in semi-infinite boundary),reducing boundary influence,numerical simulation of uniform dielectric electric field of two point current sources is carried out.The main conclusions are as follows:The following conclusions are based on the maximum relative deviation of the potential at model surface between the power supply electrodes is less than 1%.For the field numerical simulation of DC method(zero potential boundary)adopting the cuboid model(the length and width are equal),the volume of the model is the smaller in a certain precision when the height of the model is 1.75 times the distance of power supply electrodes and the width of the model is 4.35 times the distance of power supply electrodes.For the indoor model test of DC method(insulation boundary)adopting the cuboid model(length and width are equal),the volume of the model is the smaller in a certain precision when the height of the model is 3 times the distance of power supply electrodes and the width of the model is 4.35 times the distance of power supply electrodes.The volume of the hemispherical model is smaller than the cuboid model when both the boundaries are taken as zero potential boundary,the distance of power supply electrodes is same and the potential deviation at model surface between the power supply electrodes is at the same level.These conclusions are of certain significance to the design of the model both in laboratory tests and in the numerical simulation inversing field,in order that the relevant laws obtained in indoor model test and numerical simulation can be well applied in the field.
作者
刘胜
王媛
田彦
LIU Sheng;WANG Yuan;TIAN Yan(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China;Jiangsu Research Center for Geotechinical Engineering Tecihnology,Hohai University,Nanjing 210098,China)
出处
《地球物理学进展》
CSCD
北大核心
2019年第2期763-774,共12页
Progress in Geophysics
基金
国家重点研发计划课题"堤防工程安全运行风险评价理论与管理研究"(2017YFC1502603)资助
关键词
电法
边界效应
模型尺寸
优化
Direct current method
Boundary effect
Model size
Optimize
