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Abstract Abundant test results have shown that the deformation and failure response of rock material under uniaxial compression is strongly dependent on its internal structure，boundary conditions，specimen geometry，etc. This study presents a mesoscale numerical model for rock material based on continuum mechanics，and a nonlinear damage material model is adopted to describe the deformation and failure behaviors of each mesoscale finite element. To consider the spatial correlation character of physical and mechanical properties of realistic rock material as commonly observed，a spatial correlation length factor is introduced into the traditional Weibull random distribution model. Based on the established improved mesoscale random model，a series of numerical uniaxial compression tests are conducted to investigate the effects of end friction and specimen geometry on the progressive failure response of rock specimens. The results show that the end friction and specimen slenderness ratio can significantly affect the load-deformation curves and fracture patterns. The effect of specimen geometry plays a vital role even when the end friction is reduced to a small value. The mesoscale numerical study results indicate that experimental discrepancy may be diminished by lowering the end friction and increasing the specimen height/width ratio in the uniaxial compression test.
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Received: 22 May 2013
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2014, Vol. 33 
