Abstract：The interaction of different sizes of cracks in the rock is one of the key factors leading to the damage of rock. Aiming at the interaction problem of many unequal cracks existing in the rock mass，the expressions for the stress intensity factors at the crack tip of two collinear unequal cracks under far field tension were derived by Kachanov method. The interaction and the influence of two unequal cracks were analyzed. The stress intensity factors obtained by the expressions were in good agreement with the handbook of stress intensity factors. So it verified the rationality of the obtained expressions. Results show that the small crack almost has no impact on the large crack when its length is shorter than the distance between the cracks. The large crack begins to have obvious influence on the small crack when its length is longer than the distance between cracks. When the distance between two cracks reaches the length of large crack，the large crack almost has no influence on the small one.
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2014, Vol. 33 
