Abstract: Based on a pipeline tunnel project crossing an active fault, a model test was conducted to investigate the structural response of tunnels under dip-slip fault dislocation.The study analyzed surrounding rock displacement, tunnel lining deformation and strain, as well as crack evolution patterns in tunnel linings, with comparative analysis on the effectiveness of seismic cushion layers and flexible joints.The results demonstrate that during dip-slip fault movement, both surrounding rock and tunnel displacements exhibit S-shaped nonlinear distributions, with depth-dependent attenuation effects in rock displacement (horizontal attenuation rate 20%, vertical attenuation rate 33%).Under Level IV fault dislocation (40 mm strike-slip and 40 mm reverse-slip), the peak circumferential tensile strains at the left arch shoulder and right arch foot of tunnel lining within fault fracture zones reached 862.8 μɛ and 824.7 μɛ respectively, representing the most vulnerable structural components.Tunnels without seismic mitigation measures suffered flexural-shear failures with severe local spalling, while the plastic deformation energy absorption through seismic cushion layers and improved fault adaptability via flexible joints effectively reduced the core influence zone of fault dislocation to 1.5 times tunnel diameter on both sides of the dislocation plane.This mechanism significantly restricted crack propagation, demonstrating that seismic cushion layers combined with flexible joints can remarkably enhance tunnel resistance against fault dislocation.