Abstract: Further analysis is performed on hydro-mechanical-damage coupled creep constitutive model of mudstone proposed by authors in part one. Based on the continuum damage mechanics and Biot theory, the finite element equations of creep damage model are derived by considering the hydro-mechanical-damage coupling. The four-step numerical framework, i.e., elastic predictor-plastic corrector-damage corrector-permeability corrector, is provided. A nonlinear finite element analysis program is developed by the above algorithm. Based on the in-situ monitoring results of lining deformation for about 20 years, the unknown parameters of mudstone are acquired by the method of displacement back analysis. Considering the actual case of the construction of the Test Drift of radioactive waste disposal in the deep Boom mudstone formation in Belgium, the hydro-mechanical coupling process, the evolution of damage and the long term stability of the surrounding rock are studied by the proposed models. The results show that the permeability of excavation damaged zone is 120 times than that of the original mudstone after excavation. Because of the self-healing of fractures, the permeability of excavation damaged zone changes obviously and tends to self-heal with time because of the stress-water action. About 3.5 years later, the permeability of the surrounding rock is near original mudstone. The creep damage increases rapidly in the early stage and tends to stabilize gradually with time. Damage of middle part is larger than that of bottom and top part of the surrounding rock. The study can be used for predicting the long-term stability of tunnel engineering.

Key words: mudstone, constitutive model, damage mechanics, hydro-mechanical coupling, finite elements, inversion