Creep damage characteristics and slip law of weak-layer mudstone in an open mining slope

摘要

To study the creep damage mechanism and slip characteristics of the weak layers on the south slope of the Fushun WestOpen-Pit Mine, the full stress-strain and creep curves of the weak-layer mudstone under different confining pressures wereobtained via laboratory experiments. The relationship between the softening modulus and the viscoplastic parameters ofthe mudstone with confining pressure was obtained via a fitting method. A nonlinear creep damage model of the weaklayermudstone was established based on the Mohr-Coulomb strain-softening and Burgers models. A numerical calculationprogram was developed using the discrete element method to verify the reliability of the model. On the basis of the creepdamage numerical model, the large deformation and the slip law of the weak-layer slope of the West Open-Pit Mine werestudied. The results indicate that both the softening modulus and the viscoplastic creep parameters of weak-layer mudstonehave a nonlinear exponential relationship with the confining pressure. The creep damage model can characterize both thepre-peak creep damage characteristics and the post-peak strength attenuation characteristics of the mudstone. The numericalresults are in good agreement with the laboratory experimental data. The creep slip characteristics of the weak-layer slopeof the West Open-Pit Mine analyzed based on the creep damage model are basically consistent with the actual slip, and thedisplacement calculation results are also close to the field monitoring data. The research results provide scientific basis forthe prevention and control of landslide in West Open-Pit Mine.