SHPB Testing and Analysis of Bedded Shale under Active Confining Pressure

Abstract

Shale gas is the most important new energy source in the field of energy, and its exploitation is very important. The research on the dynamic mechanical properties of shale is the premise of exploitation. To study the dynamic mechanical properties of shale from the Changning-Weiyuan area of Sichuan Province, China, under confining pressure, we used a split Hopkinson pressure bar (SHPB) test system with an active containment device to carry out dynamic compression tests on shale with different bedding angles. (1) With active confining pressure, the shale experiences a high strain rate, and its stress-strain curve exhibits obvious plastic deformation. (2) For the same impact pressure, the peak stress of shale describes a U-shaped curve with an increasing bedding angle; besides, the peak stress of shale with different bedding angles increases linearly with rising confining pressure. The strain rate shows a significant confining pressure enhancement effect. With active confining pressure, the peak strain gradually decreases as the bedding angle increases. (3) As a result of the influence of different bedding angles, the dynamic elastic modulus of shale has obvious anisotropic characteristics. Shale with different bedding angles exhibits different rates of increase in the dynamic elastic modulus with rising confining pressure, which may be related to differences in the development of planes of weakness in the shale. The results of this study improve our understanding of the behavior of bedded shale under stress.

Study on the Dynamic Mechanical Properties of Metamorphic Limestone under Impact Loading

“…Zhang et al [3][4][5][6][7][8][9][10] used the improved Hopkinson test equipment to conduct conventional uniaxial impact tests on dolomite, granite, phyllite, and marble; the dynamic mechanical properties of ore and rock were studied from the stressstrain curve, failure morphology, energy distribution, and fractal dimension. Ma et al [11][12][13] conducted dynamic impact tests on artificially frozen sand and shale under active confining pressure, and the changes of stress-strain curves and strength parameters with confining pressure and strain rate were studied. Ji et al [14][15][16] conducted dynamic impact tests on granite and sandstone and analyzed the relationship between the fracture degree, strength parameters, energy dissipation, and strain rate of the two materials under different strain rates.…”

Investigation on Triaxial Dynamic Model Based on the Energy Theory of Bedding Coal Rock under Triaxial Impact Compression

“…Although many research studies have been achieved progress in the dynamic failure of layered rocks under uniaxial compression, there are few studies under triaxial confining pressure. In the triaxial impact compression test, Yang et al [24] determined that the compressive strength, peak strain, and elastic modulus of shale were affected by bedding angles under the confining pressure effect. e peak stress of shale increases linearly with increase in confining pressure, and the strain rate shows obvious confining pressure enhancement effect.…”