Constitutive model for damage of invasion surface of heavy metal-contaminated rock

Based on the acid-base proton theory, the erosion mechanism after heavy metal pollutants infiltrating into rock is discussed. The extension performances of lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn) are analyzed by using the convection-diffusion model. By way of combining the viscoelastic model and the damage monomer model, a 3D extended-fissile model is established for heavy metal contaminated rock. The deformation rules of invaded surface are discussed under different extension rates. The model fitting results are verified by the data of axial static load tests. The results show that different heavy metal pollutants have different invasion and extension performances in rock, and there is a good agreement between the experimental stress-strain curves of contaminated rock with different lithologies in the same test conditions and the fitting results of the combination model.