| It is important to study the shearing strength and deformability of rock joints under different shearing velocity in dealing with the stability of the large underground rock masses structures, which can offer the vital mechanics parameters for safety evaluation. Through the RMT-150C testing system, different undulate artificial saw-tooth joints samples casted with concrete material were designed to study the shearing strength and deformability in different shearing velocity. It is demonstrated that there is a decrease in the peak shear strength and an increase in the shear stiffness when the shearing velocity increase. The quantity changed diminish with the shearing velocity increase. Secondly,the peak shear strength and the shear stiffness both raises with increasing undulation under different shearing velocity. More"snip effect"appears with raising the undulation and the joints surface wear away when the undulation at a low level. Thirdly, the peak shear strength and the shear stiffness increase with the raising in the normal stress. When"snip effect"appears, the remaining area of the joint surface is sniped from the bottom frequently in the high normal stress. When"abrasion effect"appears, the failure is more severe or the remaining area of the joint surface was triturated directly in the same normal loading conditions. There is an non-linear relation between the several groups of variables except"the peak shear strength~ the normal stress"and"the shear stiffness ~ the normal stress".Based on the experimental results, mathematical models about the strength and the shear stiffness were developed for evaluation of different shearing velocity. Considering the shearing velocity and the non-linear character of tan(φr +α), the strength model put forward by L.Jing was improved. Barton and Choubey think that the shear stress reach the peak shear strength when the shear displacement equal to the length one percent of the whole joint surface. Based on the actual experimental results,...
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