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Three‐dimensional crack monitoring by electrical resistivity measurement
Author(s) -
Samouëlian A.,
Richard G.,
Cousin I.,
Guérin R.,
Bruand A.,
Tabbagh A.
Publication year - 2004
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2004.00632.x
Subject(s) - electrical resistivity and conductivity , anisotropy , orientation (vector space) , materials science , electrode , composite material , mineralogy , geology , geometry , optics , electrical engineering , chemistry , mathematics , physics , engineering
Summary Soil cracks formed by natural processes play a key role in water and gas transfer. Patterns of soil cracks are, however, difficult to characterize. Our aim here is to assess the effectiveness of three‐dimensional electrical resistivity surveys in detecting soil crack networks. A three‐dimensional electrical survey was carried out by a square array quadripole with Cu–CuSO 4 electrodes (electrode spacing of 3 cm). The measurements were made with two orientations (0° and 90°) on a block (26 cm × 30 cm × 40 cm) of soil while it dried for 18 days under controlled conditions. Two indexes, calculated from the apparent resistivity values, were evaluated to detect the degree of soil heterogeneity: (i) an anisotropy index based on the ratio between the apparent resistivity at 0° and that at 90°; and (ii) the angle‐array orientation corresponding to the preferential anisotropic orientation (maximum resistivity). The anisotropy index provided information on the presence of cracks and the orientation for crack width > 1 mm in the first pseudo‐depth (i.e. depth of investigation), while the angle‐array orientation provided information on crack extension for the whole pseudo‐depth. Information about the presence, position, orientation and extension of cracks can be obtained from an analysis of apparent resistivity obtained by a three‐dimensional electrical survey. Such direct analysis will help the resistivity inversion to detect the crack network.