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SONLU ELEMANLAR YÖNTEMİNİ KULLANARAK İKİ-BOYUTLU YAPILARIN ÖZDİRENÇ İLERİ MODELLEMESİ

THE RESISTIVITY FORWARD MODELING OF TWO-DIMENSIONAL FEATURES USING THE FINITE ELEMENT METHOD

Journal Name:

  • İstanbul Yerbilimleri Dergisi

Publication Year:

  • 2008

Key Words:

Keywords (Original Language):

Author NameUniversity of Author
Abstract (2. Language): 
The greatest limitation of the one-dimensional resistivity modeling is that does not take into account horizontal changes in the subsurface resistivity. To obtain a more accurate model of the subsurface, two-dimensional (2-D) modeling consisting of the resistivity changes in the vertical and the horizontal direction along the survey line must be done. In this case, it is assumed that resistivity does not change in the direction that is perpendicular to the survey line. In this study, the basic theory of the finite element method (FEM) from numerical modeling techniques is presented as two-dimensional resistivity forward modeling technique and the subsurface mesh needed for the modeling is examined. The models used in the study represent an archaeological feature. A finite element mesh with 103x19 nodes was designed to calculate the dipole-dipole apparent resistivity model responses of the 2-D models. The results of forward modeling differ from the true resistivity by approximately 2 percent for N=1 level while less than 0.5 percent for the other levels. The apparent resistivity values produced with the forward modeling are presented as pseudo-sections and they give a very approximate picture of the true subsurface resistivity distribution. The model response (result of forward modeling) can be used as an initial guide for the inversion.
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Abstract (Original Language): 
Bir-boyutlu özdirenç modellemesinin en büyük sınırlaması yeraltı özdirencinin yanal değişimlerini hesaba katmamasıdır. Yeraltının daha doğru bir modeline ulaşmak için, bir hat boyunca yanal ve düşey yönde özdirenç değişimlerini dikkate alan ikiboyutlu (2-B) modelleme yapılmalıdır. Bu durumda özdirencin araştırma hattına dik olan yönde değişmediği düşünülür. Bu çalışmada, 2-B özdirenç modelleme için sayısal modelleme tekniklerinden sonlu elemanlar yönteminin (SEY) temel kuramı sunulmaktadır ve modelleme için ihtiyaç duyulan yeraltı ağı irdelenmektedir. Çalışmada bir arkeolojik yapıyı temsil edebilecek türde modeller kullanılmıştır. 2-B modellerin dipol-dipol görünür özdirenç model tepkilerini hesaplamak için 103x19 düğümlü bir sonlu elemanlar ağı kurulmuştur. Modelleme sonuçları gerçek özdirençten N=1 seviyesinde yaklaşık %2 ve diğer seviyelerde ise %0.5’den daha az farklıdır. İleri modelleme ile hesaplanan görünür özdirenç değerleri andıran kesitler olarak sunulur ve yeraltı özdirenç dağılımının yaklaşık resmini verir. Bu model tepkisi (düz çözüm sonucu) ters çözüm için bir başlangıç rehberi olarak kullanılır.
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  • 1
37-45
  • Turkish

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