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Abstract To study the progressive failure of schistose rock，three stress thresholds，i.e. crack initiation stress ，crack damage stress and uniaxial compression peak strength ，and their relationship between each other are summarized and discussed systematically. Based on the uniaxial compression axial stress-axial/radial strain curves of Danba quartz mica schist，analysis of stress thresholds of schistose rock in progressive failure process are firstly applied to schistose rock. Stress thresholds under the three conditions of schistose foliation oriented perpendicular，parallel，and at 30° to loading direction respectively are obtained，which are compared with those of other sorts of rock in references. Results show that the crack propagation are related to rock type. Grain size of mineral，cement bond quality between mineral grains and schistose and joint plane development are all the factors to influence the progressive failure process of rock. Different stress threshold ranges of different types of rock are then got accordingly. Experimental research results of quartz mica schist indicate that due to the joint plane developments，strong anisotropy exists in the schistose rock crack propagation under uniaxial compression. This distinguishing characteristics should be considered quantitatively during underground excavation and support design.
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Received: 09 March 2011
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2011, Vol. 30 
