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Abstract Aiming at the drilling and blasting excavation method for rock，the explosive stress wave variation with time and space as well as the influence of which on the rock cracking process are analyzed with stress intensity factor. Results show that under the action of explosive stress wave，the stress in the rock media will be in compression-shear or tensile-shear state with time order. In the field near blast hole，the rock cracking is controlled by the compression-shear stress state；while the tensile-shear stress state plays a major role in rock cracking when it is far from the blast hole；with the increasing of distance，rock cracking is mainly controlled by tensile-shear stress state，which is primarily composed of a combination of radial tensile stress and tangential tensile stress. The influence of tensile shear stress state on the cracking zone cannot be ignored especially for low-strength rock.
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Received: 02 January 2013
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2014, Vol. 33 
