Analysis of dynamic tensile deformation characteristics of deep coal rock

L.G. Miao, B.M. Shi, Y.Y. Niu

Abstract


In order to study the dynamic tensile deformation failure characteristics of deep coal rock, the impact loading system of Split Hopkinson Pressure Bar (SHPB) was used to carry out the Brazilian disc splitting test under the impact for the deep coal rock samples, and the influences of impact speed and bedding angle in the coal samples on the dynamic tensile strength, failure strain and strain rate of coal samples were discussed. The results show that the larger the impact speed is, the larger the dynamic tensile strength is, but its increase gradually decreases with the impact speed increasing. The failure strain of coal samples is the maximal as the impact speed is 3.3 m/s. With the same impact speed,when the bedding is vertical to the loading direction, the failure strain of coal rock is relatively larger, however, the strain rate is the smallest. Simultaneously, when the bedding is parallel or vertical to the loading direction, the tensile failure appears in the coal samples, but if the bedding is not parallel or vertical to the loading direction, there would appear the matrix tension and the shear failure of bedding together.


Keywords


Hopkinson Pressure Bar, Brazilian disc, splitting test, dynamic tension, stress wave

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ISSN : 2180-3811       E-ISSN : 2289-814X

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