ABSTRACT
Two types of deformation can occur in rocks, i.e., brittle damage, and plastic damage, and a large number of irreversible deformations before damage occurs. The porosity of the rock is inversely proportional to the modulus of elasticity: the denser the rock, the greater the modulus of elasticity; the more developed the microfractures in the rock, the smaller the modulus of elasticity. The deformation of the rock varies greatly under different stress conditions: as the depth of the borehole becomes deeper, the pressure on the surrounding rock gradually increases, and the rock transitions from the brittle state to the plastic state; the deformation characteristics of the rock change with the nature of the load, as in the case of rocks under low-speed static load The deformation characteristics of the rock vary with the nature of the load, as the rock is plastic at low static loads and brittle at high dynamic loads.
