Effects of Cracks on the Electrical Conductivity of a Fissured Laterite: A Combined Experimental and Statistical Study

Abstract

This paper presents an experimental study of the effects of cracks on the electrical conductivity (EC) of a fissured laterite in Hunan Province, People’s Republic of China, followed by multi-variant statistical analyses of the sensitivity of the EC dependence on different crack parameters (e.g., depth, length, width, orientation, and crack density). The results show that the soil EC is highly dependent on the crack properties. In general, the EC decreases linearly as the crack depth, length, width, orientation angle, or density increases. However, the EC decreases non-linearly, and the rate of reduction increases more dramatically, as the depth of cracks exceeds 1/4 of the thickness of the soil sample. When the width of the crack increases to 2.8 cm, the EC decreases less obviously and tends to remain at a constant value. Moreover, the EC decreases more dramatically with the orientation angle when it is less than 45° (otherwise the EC decreases more slowly with the orientation angle). With an increase in crack density (or the number of cracks), the EC exhibits much higher dependence on crack depth, length, and width. Finally, of all these crack parameters, the depth and orientation are the two primary factors influencing the soil EC, and the crack length, width, and density are secondary ones. As such, the degree of effect of different crack parameters on the soil EC follows the order of depth > orientation angle > density > length > width.