Control of the Chamber in Extra-Thick Coal Seam Based on Fracture Characteristics of Coal Rock and Mass

Table 4

Mechanical parameters of the rock.

Lithology	Elastic modulus E (GPa)	σc (MPa)	Poisson’s ratio μ	GSI	mi	D	mb	s	a
Medium sand	45.5	69.4	0.26	86	17	0	9.098	0.2111	0.500
Sandstone	54.2	78.2	0.32	89	21	0	14.178	0.2946	0.500
Mudstone	15.8	17.4	0.29	65	10	0	2.865	0.0205	0.500
#3–5 coal	6.8	13.2	0.26	75	11	0.2	4.079	0.0510	0.501
Mudstone	15.2	7.2	0.31	63	12	0	3.201	0.0164	0.502
Coarse sandstone	35.1	75.6	0.25	89	20	0	13.503	0.2946	0.500