Experimental Study on Seepage of the Maokou Limestone with Fracture Surfaces

Abstract

In this paper, Maokou limestone obtained from Ningxiang of Hunan was made into standard specimens with 50 mm in diameter and 100 mm in length. The splitting method was employed to construct the fracture surfaces in specimens. Subsequently, the specimens with fracture surfaces were utilized to implement the seepage experiments with different confining pressure and volumetric stresses. Through analysis of the experimental results, it was suggested that the seepage regulations can be explained by the Darcy law when the specimens were under the low confining pressure. With increasing confining pressure, it presented the non-Darcy flow. The volumetric stress has a great impact on the permeability, which decreases as the volumetric stress increases. What’s more, under low volumetric stress, the variation of permeability is sensitive. Subsequently, the fractal dimension of specimens’ upper and lower surfaces was calculated, it was indicated that the permeability of fracture specimens increased with the mean fractal dimension of specimens’ upper and lower surfaces.