Experimental Study on Conductivity Anisotropy of Limestone Considering the Bedding Directional Effect in the Whole Process of Uniaxial Compression

Abstract

Experimental studies were conducted on the changes of the potential differences in different directions during the uniaxial compression on limestone samples parallel and normal to the bedding plane. In the test, electric current was supplied at both ends of the samples, and concurrent measurement was conducted in four measuring lines at a 45-degree angle to each other. First, the change laws of the potential differences in different directions and the similarities and differences of rock samples were summarized. In regards to the uniaxial compression properties and crack growth, the above-mentioned similarities and differences were further analyzed. Then, the anisotropy factor was introduced to further explore the response characteristics. It was found that the anisotropic changes of rock samples went through three stages during the uniaxial compression process, providing a reference for describing the properties in different failure stages of rock samples and obtaining precursory information about the fracture. Besides, the relationship between the peak stress and initial potential difference in a direction normal to the current direction was obtained by means of data fitting, providing a new method of predicting the uniaxial compressive strength of rock samples. According to the preceding analysis, this paper studied rock anisotropy by considering the bedding directional effect in terms of conductivity and provided a reference for subsequent study on rock materials' properties and engineering practices.

The Confinement-Affected Strength Variety of Anisotropic Rock Mass

“…Numerous types of rock mass have inherent or structural anisotropy, such as parametamorphic and sedimentary rocks, and other discontinuity-induced stratiform-like rock masses. Extensive compression tests have been put forward to explore the strength and failure features of various anisotropic rock masses at uniaxial and triaxial compression conditions in the laboratory, e.g., slate [ 18 , 19 , 20 ], schist [ 13 , 20 , 21 , 22 , 23 , 24 ], phyllite [ 13 , 25 ], marble [ 13 , 23 ], sandstone [ 3 ], shale [ 26 , 27 , 28 ], limestone [ 28 , 29 , 30 ], mudrock [ 31 ], columnar basalt [ 32 ], and artificially anisotropic rock specimens [ 3 , 33 ]. Numerical studies have also been conducted to investigate the mechanical behavior of anisotropic rock mass intrinsically [ 12 , 34 ].…”

Analysis of Resistivity Anisotropy of Loaded Coal Samples

“…ere are significant anisotropy of measured points in cracks and fractured zones [11,12]. Xu et al [13] explored the anisotropy change of rock under uniaxial compression by defining the anisotropy factor, which proposed that the anisotropy change tends to rise at the first macrofracture time. Chen et al [14] put forward the concept of series-parallel dominance and analyzed the law that the resistivity of anthracite increases at different temperatures as the sampling angle increases.…”

Experimental Study on Acoustic Emission of Weakly Cemented Sandstone considering Bedding Angle

“…In the uniaxial compression test of shale, Liu et al [17] used X-ray CT to scan the specimens, which illustrated the micromechanics of the failure process in the anisotropic shale. Xu et al [18] performed a uniaxial compression experiment on limestone at 0 ∘ and 90 ∘ bedding and studied the effect of bedding angle on strength characteristics and conductivity anisotropy.…”