Abstract: The damage failure mechanism and mechanical characteristics of jointed rock mass have been studied through freezing- thawing cycles and similar material test method. Through the observation of the damage failure modes and uniaxial compression test of the samples after freezing-thawing cycles, the effects of joint dip angle, joint continuity degree, joint set, joint filling depth, sort of joint filling, sample’s saturation degree and number of cycles on the damage failure mode, uniaixal compression strength and elastic modulus are studied. It is shown that the existence of joint and its physico-mechanical properties have much effect on the damage failure modes and strength. The joint dip angle affects the failure modes and strength by affecting the occurrence position of freezing-thawing cracks. The cracks become more with joint continuity degree. The effect of freezing-thawing on the samples becomes worse with number of joints. The freezing-thawing damage degree first increases then decreases with joint filling depth. The sort of joint filling has certain effect on the freezing-thawing damage degree. The freezing-thawing damage degree first decreases then increases with the sample’s saturation degree. The cracks become more and wider with the number of cycles; and its anti-freezing-thawing property is worse than that of the intact one. The above research conclusions can provide valuable references to the constructions and safety operation of rock mass projects in cold regions.

Key words: freezing-thawing cycle, jointed rock mass, damage, uniaxial compression strength, elastic modulus, failure mode