Parametric Study on the Ground Control Effects of Rock Bolt Parameters under Dynamic and Static Coupling Loads

Table 1

Rock mass properties.

Stratum	Lithology	σt (MPa)	Φ (deg)	Ei (GPa)		γ (kg·m^3)	K (GPa)
Roof	Sandy mudstone	2.10	35	1.40	0.25	2770	5.3
	Mudstone	1.97	34	3.10	0.29	2552	2.9
	Immediate roof mudstone	1.40	28	1.40	0.24	2552	2.9
Coal seam	Coal	1.30	31	0.60	0.30	1450	0.67
Floor	Sandy mudstone	3.43	36	5.13	0.27	2852	7.4
	Siltstone	4.13	47	7.13	0.22	2961	9.6

σ_t is the tensile strength, Φ is the friction angle, E_i is the elastic modulus, is Poisson’s ratio, γ is the density of rock, and K is the bulk modulus.