Experimental Study on the Influence Mechanism of the Structural Plane to Rockbursts in Deeply Buried Hard Rock Tunnels

Table 2

The stress and strain threshold between different stages of stress versus strain curves for three types of model samples.

Type of model samples	(MPa)	(MPa)	(MPa)	(10^−4)
Model sample A	8.72	29.56	36.71	60.20	0.24	0.81
Model sample B	12.61	37.53	46.27	76.93	0.27	0.81
Model sample C	16.12	39.71	48.57	90.76	0.33	0.82

, , , and are the crack initiation stress, that is, the elastic limiting stress in this paper, the crack damage stress, the peak compressive strength, and the peak strain, respectively.