Numerical simulation of bidirectional cumulative tension blasting based on smoothed particle flow method

In order to study the influence of cumulative angle on the bidirectional cumulative tension blasting, firstly, the fracture mechanics mechanism was analyzed from the principle of the bidirectional cumulative tension blasting. Secondly, the Johnson-Holmquist constitutive model was introduced to study the dynamic damage characteristics of rock. Thirdly, the numerical calculation of the bidirectional cumulative tension blasting process was carried out using the smooth particle flow method, the crack expansion processes of bidirectional cumulative tension blasting at 60°, 90° and 150° angles were reproduced and the relevant laws of rock damage development, particle distribution, stress distribution and crack propagation at the corresponding angles were obtained. Finally, the feasibility and practicability were verified through the field blasting test. The results show that at the above three types of cumulative angles, the bidirectional cumulative tension blasting can achieve the generation and penetration of directional cracks in the direction of cumulation. Although secondary cracks exist, they do not affect the generation and development of directional cracks. The smaller the cumulative angle, the larger the offset angle of crack extension in the direction of cumulation, that is, the worse the directional presplitting precision of the bidirectional cumulative tension blasting. During the directional cracking process, the explosive particles act as "air wedges" to promote the crack expansion in width and length. The field blasting test results proves that the bidirectional cumulative tension blasting has excellent directional presplitting effect. © 2022 Central South University of Technology. All rights reserved.