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Abstract Through a single fissure is being artificially prefabricated into rock-like material，strength characteristics and failure modes of deep rock mass with single fissure are studied by means of conventional triaxial compression test. The impact factors and failure conditions of shear failure along discontinuities of fissured rock mass are also discussed based on the theory of fracture mechanics. The research results show that：(1) The strength of these samples is of great concern to confining pressure，fissure inclination angle and size. (2) Fracture is external concentrated expression of damage specimens. Deformation modulus and elastic modulus are related with confining pressure，fissure inclination angle and size which has great influence on modulus. It has a lower moduli of elasticity and deformation as fissure size increases；but confining pressure and fissure inclination angle have a slight effect on the moduli. (3) The failure modes of prefabricated single fissured samples can be classified into three types，i.e. shear failure across fissured plane，sample?s own shear failure and shear failure across readjustment fissured plane when fissure size is small. (4) It has better consistency between fracture mechanics theory and the Mohr-Coulomb strength criterion if failure mode is an ideal II-type shear failure. (5) The shear failure of single fissured sample sliding across primary fissure plane depends on fissure inclination angle，size and confining pressure. Supposing fissure inclination is desired，the shear failure sliding across primary fissure plane will occur when fissure size is smaller but confining pressure is higher；and shear failure is not sensitive to confining pressure if fissure size is bigger. (6) I-type and II-type cracks of single fissured samples are found during triaxial compression test，and III-type cracks are also obtained. These conclusions can provide valuable theoretical reference for excavation，supporting design and stability analysis of underground engineering containing fissure and faults.
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Received: 27 March 2012
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2012, Vol. 31 
