Abstract
A method using two-dimensional resistivity surveys was proposed to efficiently detect the range of cracks. In the method, a conductive liquid was injected into the cracks, resistivity surveys were performed before and after the injection and the distributions of changes in resistivity were calculated. To examine the applicability of this method in the fields, numerical and field examinations were conducted. In the numerical experiment, the horizontal range estimated by the survey line parallel to the crack was found to be almost equal to the actual crack length. The vertical range estimated by the survey line perpendicular to the crack had low correlation with the depth when the depth was larger than the length. However, high correlation was observed when the depth was smaller than half of the length. In the field experiments, the horizontal range estimated by the survey line parallel to the crack detected the crack length. The range of cracks, estimated by the survey line perpendicular to the cracks, detected the crack depth when the depth was smaller than the length. The results indicate the possibility of detecting the range of cracks by estimating the crack length based on parallel survey lines and the crack depth based on perpendicular survey lines.
