The Mechanism of Rock Mass Crack Propagation of Principal Stress Rotation in the Process of Tunnel Excavation

Table 1

Physical and mechanical parameters of rock mass.

Density of rock mass ρ (kg·m^−3)	Modulus of elasticity E (GPa)	Internal friction angle φ (°)	Cohesion c (MPa)	Poisson ratio μ	Tensile strength σt (MPa)
2700.0	8.0	36.0	0.7	0.2	0.5