Penetration Form of Inter-Hole Cracks under Double-Hole Blasting Conditions with Inclined Fissures

During blasting construction in tunnel engineering, an inclined fissure near the blast hole produces “Z” type of over-excavation and subsequently affects overall effect stability tunnel. In this work, dynamic caustics testing was used to study burst propagation mode penetration form explosive cracks at different positions between holes under double-hole conditions. Results showed that existence gently changed law stress wave. The dominant fracture surface formed vertical direction borehole fracture. Finally, crack penetrates “Z”-type over-excavation, which analyzed by test. expansion velocity reached maximum reflection explosion wave then decreased with attenuation intensity. peak increasing distance prefabricated borehole, intensity factor tip immediately its value after detonation, oscillation decreased. These research results can serve a basis for reducing condition optimizing parameters.