LAUSR

Abstract Recently, the application of deep hole presplit blasting (DHPB) in underground-engineering excavation has increased, but the research on deformation characteristics and failure mechanism of DHPB is relatively less, and lack of relevant numerical simulation verification. Owing to the above situation, the deformation characteristics and failure mechanism of DHPB are obtained through numerical simulation and model testing of samples under horizontal compressive stress, compressive vertical stress and no compressive stress, and the shape analysis of presplit cracks after presplit blasting. This work demonstrates when presplit blasting is performed in underground engineering, the angle between the connection orientations of the blasthole and the compressive stress orientation should be avoided at 90° as far as possible. When the deep confining pressure is not uniform, the orientation of the minimum principal stress should be at an angle of 90° to the orientation of the blasthole connecting line as far as possible. Furthermore, the orientation of the maximum principal stress should be consistent with the orientation of the blasthole connecting line as far as possible.