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Abstract To investigate mechanical properties of the gneiss in deep stope at Hongtoushan copper mine，Fushun，and further study the mechanism concerning slight rock burst and time-efficient deformation failure，the standard triaxial specimens are made from the core to carry out the complete failure processing triaxial test，unloading confining pressure under constant deviator stress test and creep test by Rockman 207 triaxial apparatus. The test results show that：(1) The relevancy of wave velocity-density-strength is not strong and the scatter is significant in uniaxial and triaxial results. (2) The brittle failure behaviour on hard rock is observed when the confining pressure is lower than 40 MPa，which would lead to a potential rockburst. (3) The strength in the unloading confining pressure under constant deviator stress tests is lower than that in the conventional triaxial. The plastic deformation is apparent during the loading，which indicates that the unloading path affects the rockburst. (4) Creep deformation is not measured under low stress level and the step deformation can be seen prior to the typical accelerated creep under high stress level. The failure mode of the gneiss sample in the creep test is with high similarity in comparison with the practical rib spalling in situ.
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Received: 05 November 2012
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2013, Vol. 32 
