Figure 2

Uniaxial compression experiments. (a) deformed coal sample; (b) stress–strain curves of coal sample; (c) deformed siltstone sample; and (d) stress–strain curves of siltstone sample.

Uniaxial compression experiments. (a) deformed coal sample; (b) stress–strain curves of coal sample; (c) deformed siltstone sample; and (d) stress–strain curves of siltstone sample.