Damage constitutive model and variables of cracked rock in a hydro-chemical environment

The mass of underground rock was continuously influenced by the physical, mechanical, and chemical effects of seepage flow. The interaction of water and rock is now a research subject at the forefront in geotechnical engineering in fields as diverse as nuclear waste disposal, dam foundation construction, tunnelling, slope dynamics, and mineral resource utilization. The multiple coupling processes and mechanisms within the stress, seepage, and chemical domains of the rock mass in a hydro-chemical environment are analyzed. Based on fracture and general damage mechanics, a constitutive model using variables of the cracked rock under uniaxial compression and chemical solution erosion was established, and the rock damage represented by the porosity resulting from the hydro-physicochemical interaction is deduced. When compared with the results of uniaxial compression tests and porosity measurements of granite specimens treated with acidic chemical solutions, the constitutive model is seen to be in good agreement with stress-strain curves of granite under uniaxial compression and thus appropriate for describing the progressive rock damage that occurs under chemical erosion. The damage may be represented as the hydro-physicochemical damage level of the rock. Then, based on the damage constitutive model and expression pattern, a numerical simulation that takes into consideration the hydro-chemical damage effect shows that the variation in seepage in the deep mining of the Sanshandao Gold Mine is continuously expanding and exerts a great influence on the stability of the rock mass.