An Improved Numerical Simulation Approach for the Failure of Rock Bolts Subjected to Tensile Load in Deep Roadway

Table 2

Mechanical parameters of the surrounding rock and concrete spray layer.

Rock strata	Thickness (m)	Density (kg·m^-3)	Bulk modulus (GPa)	Shear modulus (GPa)	Internal friction angle (°)	Cohesion (MPa)	Tensile strength (MPa)
Sandy mudstone	4.8	2500	0.73	0.44	33	2.0	0.74
Coal	15.4	2200	0.40	0.21	25	1.5	0.50
Poststone	19.8	2500	1.16	0.70	35	2.2	0.85
Concrete spray layer	0.1	2500	1.60	0.97	37	3.0	1.20