Stability evaluation of tunnels in steeply dipping layered rock mass using numerical models: a case study.

Tunnel stability is a critical factor in complex geological conditions, particularly in rock masses with steeply dipping layers. Among widely used methods, the Convergence-Confinement Method (CCM), a prevalent two-dimensional (2D) approach, effectively captures the relaxation process preceding support installation. However, most studies focus on homogeneous or horizontally layered rock masses, often overlooking the influence of steeply dipping, and layered geological formations.