AN Improved Smoothed Particle Hydrodynamics Method Applied to Crack Propagation and Deformation of Circular Deep Tunnels in Layered Rock

ABSTRACT To investigate the processes of crack propagation and deformation failure of surrounding rock induced by deep tunnel excavation in layered rock masses, the conventional smoothed particle hydrodynamics (SPH) method is improved. A novel numerical simulation approach, termed layered rock particle hydrodynamics (LRPH), is developed and corresponding models are established. The distribution of cracks, deformation at monitoring points, and the number of fractures at different strain stages are analyzed to examine the influences of bedding dip angle, lateral velocity coefficient, and deep tunnel location on the deformation and failure behavior of the surrounding rock. The numerical results demonstrate that LRPH overcomes the limitations of traditional mesh‐based methods and is capable of dynamically capturing the crack propagation process. The presence of bedding significantly affects the initiation location and subsequent propagation direction of cracks, leading to an increase in fracture density and greater convergence deformation of the surrounding rock. Bedding dip angle, lateral velocity coefficient, and deep tunnel position all influence the orientation of crack development, while a bedding dip angle of 45° has a relatively minor effect on the overall convergence deformation of the surrounding rock. The lateral velocity coefficient plays a dominant role in tunnel‐induced damage: higher coefficients result in more developed fractures and larger displacements at the deep tunnel crown. The findings provide valuable insights into the deformation and failure mechanisms of deep tunnels excavated in layered rock masses and further promote the application of SPH‐based methods in tunnel engineering.