The degree of crushing blocks during the open -air blasting is the main measurement standard for comprehensive costs such as drilling, shovel, transportation, and follow -up process. The single consumption of explosive is the main influencing factor. Generally, the blasting model test is used to conduct related research. There are some disadvantages such as high cost and large error of test results. Based on the basic theory of explosion rock breaking rock, the use of basic mechanical testing equipment for modeling materials for single-axis compression, elastic modulus, fracture toughness and other tests, calibrate RHT's model parameters, use numerical simulation software LS-Dyna and SPH The particle flow algorithm builds a three -dimensional open -roof blasting numerical simulation model. For the first time, the numerical simulation results of blasting block are accurately counted, and the law of the change of blasting block with explosive consumption is systematically studied. The results show that the maximum size and average size of rock blocks are affected by the amount of explosive used. The single consumption is greater than 0.23 kg·m-3, the maximum size of rock blocks is less than 240 mm, and the single consumption is between 0.31 and 0.39 kg·m-3 and between 0.55 and 0.71 kg·m-3, and the maximum size of rock blocks decreases rapidly. The maximum size of 240 mm, 220 mm, 180 mm, and 140 mm is obviously distributed; the degree of blocks of different single consumption is obviously different, and the average size of the single consumption of 0.23 ~ 0.55 kg·m-3 is reduced rapidly, and the single consumption is greater than 0.55 kg·m-3. Explosive diameter is greater than 24 mm, the average size of the rock block fluctuates between 60-80 mm, and the average block size changes slowly. The G-G-S function passes the distribution rate of block degree distribution, and the correlation coefficients are above 0.9. High correlation verification The method of calculating the use of particle flow (SPH) to calculate the calculation of the rock broken block is feasible; The statistical results of the lumpiness distribution achieved by SPH particle flow algorithm are basically consistent with the traditional model experiment, and have higher accuracy; The suitable single consumption is calculated according to the block requirement. The evenness index n fluctuates within a certain range and decreases overall; 0.39 ~ 0.55 kg·m-3, 0.63 ~ 0.71 kg·m-3 segment is rising, 0.55 kg·m-3 is the largest, Well-broken rock, the average block is small, and the largest size in the middle connection section decreases, showing abnormal fluctuations, showing abnormal fluctuations Decrease, this change law also applies to the rapid change of the maximum mass.