Simulation study on the damage evolution of rock by Two-Step wedge cut blasting under high in-situ stress

This study investigates the two-step wedge cut blasting technique, crucial for deep hard rock excavation under high stress. Our research assumes that this method significantly influences rock damage and fragmentation under varying stress conditions. Data from numerical simulations and experiments reveal the following:First-stage cutting initiates cracks and local damage in the cut area, while second-stage cutting propagates these cracks, forming a wider damage zone around the cavity. Under hydrostatic stress exceeding 20 MPa, radial crack growth is restricted, with damage concentrated near blast holes, exhibiting uniform compressive cracks. In non-hydrostatic fields, cracks grow in diverse directions with intersecting patterns. High in-situ stress enhances the efficiency of explosive energy usage, resulting in more complete rock breakage and a larger cavity volume. The non-hydrostatic field shows higher energy-release efficiency than the hydrostatic one, creating a wider failure-extension area.These findings indicate that stress conditions considerably affect rock fragmentation and cavity formation in two-step wedge cut blasting. The data was obtained through calibrated numerical models in LS-DYNA and experimental tests, ensuring reliability. This research offers valuable insights for optimizing blasting design in deep hard rock excavation under high stress, providing both theoretical understanding and practical guidance for improving efficiency in such challenging environments.