<p>The creep behavior of rock-like materials containing inclined soft interlayers was investigated in cyclic loading–unloading experiments. The stress–strain response, long-term strength, and deformation and failure characteristics were examined to characterize the time-dependent behavior of the specimens. The results show that higher seepage pressures promote more pronounced crack propagation and lead to a reduction in long-term strength. To capture the accelerated creep observed in the experiments, a nonlinear viscoplastic element was introduced to enhance the nonlinear Burgers model, resulting in a nonlinear seepage–creep constitutive formulation. Model parameters were determined by fitting the experimental data using the Levenberg–Marquardt least-squares algorithm. The proposed model accurately describes the instantaneous elastic response, primary creep, and steady-state creep, and effectively captures the accelerated creep stage. These findings provide valuable theoretical and practical insights into the coupled seepage–creep behavior of rock masses containing soft interlayers</p>