变步长激发极化法有限元数值模拟  

FINITE ELEMENT NUMERICAL SIMULATION ON IP METHOD WITH ADJUSTABLE STEPS

作　　者：杨晓弘[1] 何继善[1] 童孝忠[1] 

机构地区：[1]中南大学信息物理工程学院,长沙410083

出　　处：《物探化探计算技术》2008年第3期212-215,共4页Computing Techniques For Geophysical and Geochemical Exploration

摘　　要：用改变剖分步长的方法对三维地电模型进行激发极化法正演模拟计算。首先,在给出三维地电模型异常电位的边值问题与变分问题的基础上,通过对三维激电模型进行变步长的六面体剖分,将异常体部分用较短步长的单元进行加密剖分,并在各个单元上进行插值,于是得到其总刚度矩阵;然后用变带宽方式对其进行编号存储,并选用成熟的LDLT方法求解大型稀疏矩阵,运用等效视电阻率方法求取地表视极化率值。通过用中间梯度装置对几例典型的激电模型进行了正演计算,结果表明,该方法能够达到满意的精度和效果,从而为激发极化正演解释提供有益的帮助。In the paper the FEM with adjustable step to modeling IP sounding on 3-D geoelectric section is presented. First, based on the 3-D boundary value and variation equation of electrical field on a given 3-D structure, the model with hexahedron element on 3-D geoelectric section is analyzed with more short step in the isomer part of the geoelectric section. Then interpolation is applied in each element to form stiffness matrix stored with the various-band-width method and the sparse matrix is solved with mature LDLT method. The equivalent resistivity method is used to calculate the polarization rate of the model. Then the forward modeling of several typical IP models with schlumberger array show that this method can improve the calculation speed and precision,so that it is very useful in the forward interpretation of IP method.

关 键 词：激发极化法 有限单元法 三维地电断面 中间梯度法 

分 类 号：P631.324[天文地球—地质矿产勘探]