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Abstract Based on the theory of particle discrete element，the crack propagation and failure mode of Hwangdeung granite with two pre-existing flaws are researched under biaxial compression. The results show that confining pressure has a significant effect on crack propagation and failure mode. The effect of the horizontal flaw shielding the inclined flaw from a vertical load enhances with the increase of confining pressure. And the larger flaw inclination angle is，the more obvious the protective effect is. When flaw inclination angle ，the number of microcracks increases with the increase of confining pressure at the end of tests. When ，the number of microcracks firstly increases and subsequently decreases with the increase of confining pressure. Crack initiation stress of rock specimen increases with the increase of confining pressure except . Peak strength of rock specimen also increases with the increase of confining pressure. Confining pressure has different effects on crack initiation stress and peak strength of rock specimen with different flaw inclination angles. The size relation of crack initiation stress and peak strength of rock specimen with different flaw inclination angles exhibits no clear increasing or decreasing trend under the same confining pressure，for they are related to failure modes of rock specimen. On the whole，confining pressure has the largest impact on the mechanical properties of rock specimen with flaw inclination angle of 60°.
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Received: 01 March 2012
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2013, Vol. 32 
