Abstract:Determination of the dynamic strength characteristics and stress evolution law of rock mass after blasting is the key to study the rock mass failure characteristics near the blasthole, and utilization of a reasonable dynamic strength model directly determines the correctness of the calculated results of the gunhole failure zone. The calculation formula of hole damage zone related to rock mass ratio has been studied with both theoretical and site experimental analyses. Based on the displacement compatibility equation of cylindrical wave, the formula for calculating the strain rate of rock mass near the blasthole was derived and applied to the rate-dependent dynamic compression and tensile strength criteria related to rock mass. The calculation model of the failure area of blasthole was also established. So that the error of the calculation result brought by selecting parameters according to experience was effectively avoided. At the same time, based on the measured result of bench blasting in practical engineering, the destruction characteristics at the bottom of the residual hole under different borehole diameters and charge conditions were recorded. Furthermore, the failure characteristics of residual holes in rock bottom were analyzed. The theoretical calculation results of fracture zone were close to the experimental statistical results under different borehole diameters and charge conditions. It verified the accuracy of the calculation formula through comparisons between measured and calculated values, which had important reference significance for the actual prediction and numerical simulation of blasting damage area of practical engineering.