桂林理工大学学报
桂林理工大學學報
계림리공대학학보
JOURNAL OF GUILIN UNIVERSITY OF TECHNOLOGY
2014年
1期
30-38
,共9页
大地电磁%二维%垂直断面地形%电导率线性变化%有限单元法%正演
大地電磁%二維%垂直斷麵地形%電導率線性變化%有限單元法%正縯
대지전자%이유%수직단면지형%전도솔선성변화%유한단원법%정연
magnetotelluric%two dimension%upright discontinuity topography%linear variable conductivity%finite element method%forward modeling
为模拟复杂地形及地质结构，利用三角单元进行剖分，给出了具有垂直断面地形的简单网格剖分方法；电导率和电磁场值在单元内线性变化，推导出大地电磁TE （横电）模式有限单元法系数矩阵，利用高斯积分计算TM （横磁）模式有限单元法系数矩阵；计算辅助场时，在垂向采用二次拉格朗日插值计算主场值的垂向偏导数；用有限单元法对一维及二维模型进行视电阻率及相位计算，与前人计算结果进行了对比检验，计算结果与解析解的相对均方差小于0.17％；计算了垂直间断面地形的视电阻率断面图。
為模擬複雜地形及地質結構，利用三角單元進行剖分，給齣瞭具有垂直斷麵地形的簡單網格剖分方法；電導率和電磁場值在單元內線性變化，推導齣大地電磁TE （橫電）模式有限單元法繫數矩陣，利用高斯積分計算TM （橫磁）模式有限單元法繫數矩陣；計算輔助場時，在垂嚮採用二次拉格朗日插值計算主場值的垂嚮偏導數；用有限單元法對一維及二維模型進行視電阻率及相位計算，與前人計算結果進行瞭對比檢驗，計算結果與解析解的相對均方差小于0.17％；計算瞭垂直間斷麵地形的視電阻率斷麵圖。
위모의복잡지형급지질결구，이용삼각단원진행부분，급출료구유수직단면지형적간단망격부분방법；전도솔화전자장치재단원내선성변화，추도출대지전자TE （횡전）모식유한단원법계수구진，이용고사적분계산TM （횡자）모식유한단원법계수구진；계산보조장시，재수향채용이차랍격랑일삽치계산주장치적수향편도수；용유한단원법대일유급이유모형진행시전조솔급상위계산，여전인계산결과진행료대비검험，계산결과여해석해적상대균방차소우0.17％；계산료수직간단면지형적시전조솔단면도。
In order to simulate complex topography and geological structure,triangle element is used to do the grid mesh in two dimension magnetotelluric FEM (Finite Element Method)forward modeling.Conductivity is linear variable in each triangle element,which accords better with field geological condition.An easy mesh method for upright discontinuity topography is constructed.The FEM coefficient matrixes of TE (Tansverse E-lectric)mode are deduced and the coefficient matrixes of TM (Tansverse Magnetic)mode are calculated by Gauss integral.Quadratic Lagrange interpolation is used to calculate the vertical derivative to calculate auxiliary field.In order to test the forward modeling method,the apparent resistivity and phase of one and two dimen-sion models are calculated.The relative square deviation of FEM and analytical results are less than 0.17%. A model of discontinuity topography is also simulated in this paper.
