| Stability analysis and evaluation of the surrounding rock, as the key of the Tunnel Engineering, is the base of tunnel design, construction and its safe and effective operation. Rock blasting damage is the important factor that affects surrounding rock stability in the tunnel. Blasting influence on the stability of surrounding rock is reflected in the following two aspects. One is to deteriorate the mechanical properties of rock and reduce its strength and elastic modulus. The other is to produce cracks in the rock or expand its original cracks so that the rock integrity can be influenced. Blasting affected areas are divided into 3 parts according to the failure characteristics of the rock: blasting neighboring region (crush region), (fracture region) and blasting remote region (stretch region) during the blasting stage, and the difference of the damage is unlike. At the neighboring region, the value of the damage D can be considered as 1, and at the blasting midst region, the value of the damage D must be 0 |
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