Study on the Acoustic Emission Characteristics of Different Rock Types and Its Fracture Mechanism in Brazilian Splitting Test

Abstract

In order to investigate the relationship between rock microfracture mechanism and acoustic emission (AE) signal characteristic parameters under split loads, the MTS322 servo-controlled rock mechanical test system was employed to carry out the Brazilian split tests on granite, marble, sandstone, and limestone, while FEI Quanta-200 scanning electron microscope system was employed to carry out the analysis of fracture morphology. The results indicate that different scales of mineral particle, mineral composition, and discontinuity have influence on the fracture characteristics of rock, as well as the b-value. The peak frequency distribution of the AE signal has obvious zonal features, and these distinct peak frequencies of four types of rock fall mostly in ranges of 0–100 kHz, 100–300 kHz, and above 300 kHz. Due to the different rock properties and mineral compositions, the proportions of peak frequencies in these intervals are also different among the four rocks, which are also acting on the b-value. In addition, for granite, the peak frequencies of AE signals are mostly distributed above 300 kHz for granite, marble, and limestone, which mainly derive from the internal fracture of k-feldspar minerals; for marble, the AE signals with peak frequency are mostly distributed in over 300 kHz, which mainly derive from the internal fracture of dolomite minerals and calcite minerals; AE signals for sandstone are mostly distributed in the range of 0–100 kHz, which mainly derive from the internal fracture of quartz minerals; for limestone, the AE signals with peak frequency are mostly distributed in over 300 kHz, which mainly derive from the internal fracture of granular-calcite minerals. The relationship between acoustic emission signal frequency of rock fracture and the fracture scale is constructed through experiments, which is of great help for in-depth understanding of the scaling relationship of rock fracture.

Acoustic emission characteristic of sandstone and sandstone like material under multi-path loading

“…Zha et al [ 16 ] analyzed the spatiotemporal evolution of AE parameters and rock damage development under different loading modes. Li et al [ 17 ] established, through experiments, the relationship between the frequency of rock fracture AE signals and crack scale. Zhao and Liu [ 18 ] discovered that the cumulative AE energy suddenly increases before reaching peak strength, correlating positively with the development of penetrating cracks.…”

Classification of Microseismic Signals Using Machine Learning

“…Li [31] conducted a comparative analysis of the differences in acoustic emission count variations during the failure process of red sandstone under three different loading conditions: uniaxial compression, Brazilian splitting, and shear. Li [32] compared the differences in acoustic emission B-values and peak frequency variations during the failure process of rocks from different geological formations, such as granite, sandstone, and marble, within the same region under Brazilian splitting loading conditions. These studies show that the characteristics of microseismic signals generated by different rocks under stress vary significantly, and accurately identifying the types of rocks that generate microseismic signals can help to more precisely judge the stress state and potential failure location inside the rock mass, thus improving the accuracy of early warning systems.…”