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Abstract In order to study the effects of joint location and size on comprehensive shear strength of rock mass，cement mortar is selected as model material and specimens were prepared with prefabricated joints of the same size at different locations and with joints of various sizes at the same location，and shear tests were conducted under various normal stress of 3 different joints undulating angles. Experimental results indicate that shear strength increases with the increase of normal stress when the location and size of the joint are definite，and when the joint is located in the middle of the specimen，the shear strength and cohesion are the lowest，while largest when the joint is located at the back and fall in between them when located in the front of the specimen，but change law of the internal friction angle with different joint location is not obvious. When the joint location is definite，the longer the joint the lower the shear strength and cohesion. Moreover，shear strength of joint decreases linearly with increase of joint length. Effects of joint location and size on comprehensive shear strength of rock mass may be decided by both the strength parameters of joint and rock bridge and damage degradation of rock bridge. Position of joint should be considered when shear strength of in-situ jointed rock mass is estimated.
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2015, Vol. 34 
