Energy Release Analysis of a Severe Rockburst in a Headrace Tunnel Crossing a Tectonic Stress Zone

Table 3

Mechanical parameters of sandstone and shotcrete.

Materials	Young’s modulus (GPa)	Poisson’s ration	Cohesive strength (MPa)	Friction angle (°)
Sandstone	20	0.25	4.3	42
Shotcrete	25	0.2	—	—