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Abstract Using cement mortar as similar material，joint specimens with three joint wall strengths and five asperity angles were prepared. Then a series of cyclic shear tests are performed at four normal stresses on the cyclic shear test apparatus. Tests results show that，shear stress-shear displacement curve has peak strength of each shear cycle，and the shear strength of joints gradually decrease with the cyclic number increase. The peak shear strength of joint after n cycles is expressed as ，then the = / is defined as shear strength ratio，so as to characterize the degree of strength deterioration under cyclic shear loads. Based on a variety of cyclic shear test results and ，the relationships between peak shear strength of joints and shear cycles are analyzed. By comparing the results under different experimental conditions，the effects of asperity angles，joint wall strength and normal stress on the joint mechanical properties are also analyzed.
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Received: 17 May 2011
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2011, Vol. 30 
