What is the elasticity, plasticity, and brittleness of rock?

When cylindrical and spherical isobaric heads are pressed into rocks of different properties, three different forms of pressure-push-in depth (p-h) curves may appear, as shown in Figure 1.

Fig.1 Schematic diagram of pressure-pressure relationship of cylindrical indenter pressed into rock

(α) brittle rock; (b) plastic brittle rock; (c) plastic rock

Each curve has an approximate linear phase. At this stage, the indentation depth increases proportionally with the increase of pressure. After the pressure is released, the rock will return to its original shape and volume without any residual deformation. This property is called elasticity. .

After the rock is unloaded, the ability to retain partial deformation is called plasticity.

Before the destruction, there is basically only the rock in the straight line stage, or the force state reaches a certain limit degree, and then the violent destruction occurs very quickly. This property is called brittleness.