<p>This study presents an enhanced cohesive zone model (CZM) implemented within a two-dimensional intrinsic FEM-CZM framework for simulating the deformation and failure of layered soft rock tunnels. A key innovation is the integration of the Mohr–Coulomb criterion into the CZM formulation, enabling the model to capture shear-dominated failure. The constitutive parameters, particularly the equivalent elastic modulus under Delaunay triangulation meshing, are systematically calibrated to ensure the simulated stress–strain response reproduces the full deformation-failure process observed in laboratory tests. An exponential nonlinear term is introduced into the constitutive law to represent the initial compaction behavior of soft rock masses, while bilinear and multilinear traction-separation laws are employed to capture the transition from brittle to quasi-brittle behavior under varying confining pressures. The enhanced CZM is applied to simulate the stability of layered soft rock tunnels under different dip angles and lateral pressure coefficients. The results reveal the deformation-failure patterns and quantitatively assess the influence of dip angle and lateral pressure coefficient on tunnel stability, providing insights for the safety assessment and design of tunnels in layered soft rock masses.</p>