Experimental Study on Damage Evolution Characteristics of Rock-Like Material

Based on the continuum damage mechanics, the damage variable of wave velocity is defined, and the piecewise curve damage evolution of rock material constitutive model is constructed. Using uniaxial compression experiments, using ultrasound on the wave velocity in the process of compression test, the relationship between strain and velocity is obtained, and then the experimental parameters of constitutive model were analyzed. Analysis shows that: All specimens had similar damage variable strain curve, which is roughly "S" type. The damage variable-strain constitutive model based on the change of wave velocity is divided into four stages, which are brittle damage zone, damage transition zone, damage extension zone, and fracture failure zone. At the peak value, the damage variable with the increase in strain amplitude increased sharply and the initial crack width increased significantly, and the crack extension is very unstable. Then the damage fracture evolution characteristics of the specimen during loading are obtained.