Deformation failure characteristics of coal–rock combined body under uniaxial compression: experimental and numerical investigations
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The deformation and failure behaviour of coal–rock combined body under uniaxial compression were investigated experimentally and numerically. The mechanical parameters, including the uniaxial compressive strength (UCS), elastic modulus and full-scale stress–strain curves, were obtained. A detailed analysis of the evolution of the internal cracks based on X-ray computed tomography (CT) observations and acoustic emission (AE) locations is presented. The experimental results show that the mechanical properties and deformation failure characteristics of the coal–rock combined body were governed mainly by the coal. The UCS and elastic modulus of the coal–rock combined body were slightly larger than those of the coal and most of the cracks occurring in the coal were a result of the uniaxial compression. Furthermore, a numerical simulation was conducted to validate the experimental evidence. Finally, based on this understanding, a constitutive relationship was proposed using the natural strain described in Hooke’s law for accurate modelling of the deformation of the coal–rock body. A good agreement was obtained between the numerical results and experimental data during the pre-peak regime.
KeywordsCoal–rock combined body Uniaxial compression Deformation failure Constitutive relationship
The authors gratefully acknowledge the support from the National Natural Science Foundation of China (51622404 and 11572343), Yueqi Distinguished Scholar of CUMTB, the State Key Research Development Program of China (2016YFC0801404), National Program for Support of Top-notch Young Professionals and China Postdoctoral Science Foundation (2017 M620048 and 2018 T110103).
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