Abstract
Joints and other discontinuities in rock masses cause overbreak, underbreak, and instability during tunnel blasting. This paper reviews recent advances in damage control for jointed rock tunnels and validates key findings through numerical simulations. At the microscale, joints affect stress wave propagation, energy distribution, and crack growth patterns. We used ANSYS/LS-DYNA 19.0 to simulate 16 parametric cases and quantify the effects of joint geometry on blasting response. Results show that joint-to-borehole distance is the primary factor controlling damage distribution. A joint dip angle of 45° produces the most severe damage anisotropy, with cracks propagating preferentially along the joint plane. A three-dimensional tunnel model was then developed to assess water-pressure blasting. Compared with conventional methods, water-pressure blasting reduces damage depth by 20.4% and peak particle velocity by 57.6% in jointed rock. The paper also discusses parameter optimization methods, intelligent evaluation techniques, and dynamic control strategies. Engineering recommendations are provided for different geological conditions, including horizontally layered rock, inclined joints, and deep high-stress environments. This work offers both theoretical insights and practical guidance for precision blasting in jointed rock tunnels.