Triaxial compression test were carried out by using serve-control rock mechanics test system, through the stress and strain curve and failure characters of rock specimens, in order to analyze the influence of strength and deformation with different fissure angle and length under different confining pressures of jointed rock, it was found that the cohesive force dropped seriously during the residual strength phase, which indicated the specimens had formed the macro transfixion crack, in this case, the friction of the fracture surface bore the bearing capacity. At the same time, the relationship between the energy and strength and deformation of fractured rock were discussed from the perspectives of energy dissipation, in considering friction and without considering friction conditions, changing mechanism of strain energy in the fractured rock mass crack surface were revealed.
There are a large number of joints, crack, holes and other defects in natural rock, and at the same time, the rock mass is composed by a variety of mineral heterogeneous body, a large number of geotechnical engineering practice show that the geotechnical instability is related to their internal joints crack expansion and transfixion, such as dam failure took place in Malta Pasay dam of French, slope instability happened in Wa Yiang of Italian and the Lianzi cliff landslide in Yangtze river three gorges of china (S.C. Li, et al., 2007). So it is great significance to recognize the mechanical properties of fractured rock from the joints, cracks and other defects.
At present, a large number of mechanical properties of fractured rock triaxial compression test have been carried out at home and abroad, literature (M. Prudencio&M.V.S. Jan, 2007) carried out a set of prefabricated fissures biaxial compression test by intermittent jointed rock mass, and analyzed the impact of parameters change such as joint spacing, joint angle, joint arrangement and intermediate principal stress to the failure modes, strength and deformation characteristics of rock mass; Some researchers (E.T. Brown et al. 1970a, b) have researched joint spacing, joint set number, joints through degree on rock mass strength, deformation and failure mode through pile of masonry triaxial compression test; Conventional triaxial compression test were carried out through natural festival grounds marble specimen in Jinping diversion tunnel, The results showed two failure modes-wearing cut joints surface damage and along the joint plane slip (H.Z. Li. et al. 2008); literature (S.Q. Yang et al. 2007, 2008) have carried out conventional triaxial compression test with two broken pre-crack coarse marble to research deformation and strength characteristics under different confining pressure, and through the Coulomb and Hoek-Brown strength criterion to obtain this sort of rock strength parameters; Some scholars (T.C. Li, et al. 2010) have selected out of a ceramic production specimen which with the similar physical and mechanical properties of rock, and presented a round coin-shaped fissure on specimen central and carried out triaxial loading process real-time CT scan test to study fracture rock propagation law in triaxial loading effect; Other academics (X.P. Li, et al. 2012a,b) through precast single fissure which have specific angle and the specific size in high strength silicon powder mortar material, to observe single crack sample destruction form, there are three modes: tensile type crack (I type), sliding mode crack (II type) and tearing mode crack (III type), meanwhile the literature analyzed influence factor of single fractured rock mass along the structural plane shear failure through fracture mechanics theory, and discussed the failure conditions of fractured rock mass sliding along the structure surface.
