CAJ | 학술논문

常规的可控源电磁法理论在计算视电阻率公式上,多半采用其电磁场的渐近特征,难以直接反映全区视电阻率的值,及直观地显现地下介质的地质构造.文中采用水平偶极子激发的电磁场,提出了电场的全区精确表达式,直接计算出大地电阻率.利用汉克尔数值滤波算法和逆样条插值算法对水平层状电磁场进行正演计算,并与计算的卡尼亚视电阻率的对比和野外试验结果表明:该方法的结果在远区等价卡尼亚电阻率,在近区和过渡带则明显地改善了卡尼亚电阻率的非波场区场畸变,从而能更好地接近基底的真电阻率,更形象地反映了地下介质的垂向电性变化.
상규적가공원전자법이론재계산시전조솔공식상,다반채용기전자장적점근특정,난이직접반영전구시전조솔적치,급직관지현현지하개질적지질구조.문중채용수평우겁자격발적전자장,제출료전장적전구정학표체식,직접계산출대지전조솔.이용한극이수치려파산법화역양조삽치산법대수평층상전자장진행정연계산,병여계산적잡니아시전조솔적대비화야외시험결과표명:해방법적결과재원구등개잡니아전조솔,재근구화과도대칙명현지개선료잡니아전조솔적비파장구장기변,종이능경호지접근기저적진전조솔,경형상지반영료지하개질적수향전성변화.
The electromagnetic theory of conventional CSAMT mostly adopts its approximate characteristic in calculating the expression of the apparent resistivity. This method is difficult to reflect directly resistivity values at full-frequencies and show clearly geological structure in the subsurface. The paper presents a new full-zone expression of the electrical field to calculate directly and accurately earth resistivity by using the electromagnetic fields from horizontal electric dipole. Using Hankel digital filter algorithm and inverse spine interpolation algorithm to simulate electromagnetic fields of the horizontal layers, we contrast the calculational Cagniard apparent resistivity with its results and field experimentation. The results are equal to Cagniard resistivity in far-field ,but in near-field area and transient area, the results have greatly improved the strong distortion of Cagniard resistivity. So the results can reach the true resistivity and indicate the changing features of conductivity of subsurface much better than Cagniard resistivity does.