Mechanical Parameters of Deep-Buried Coal Goaf Rock Mass Based on Optimized GSI Quantitative Analysis

Table 9

Rock mass mechanical parameters of goaf roof.

Roof strata	GSI					S	a	Compressive strength (MPa)	Deformation modulus (GPa)	Friction angle (°)
9 coal roof sandstone and shale	44.3	46.9	20.6	6	0.266	0.29 × 10^−3	0.508	3.12	1.49	38.5
11 coal top roof shale	46.8	48.5	28.4	6	0.330	0.46 × 10^−3	0.507	3.64	2.53	37.3
11 coal lower roof sandstone	56.6	75.2	21.3	9	1.074	2.8 × 10^−3	0.504	10.60	4.46	49.5
13 coal top roof shale	67.9	37.1	25.2	6	1.488	17.5 × 10^−3	0.502	6.97	12.06	42.7
13 coal middle roof sandstone	70.0	61.2	34.9	9	2.511	23.9 × 10^−3	0.501	14.56	18.73	50.3
13 coal lower roof limestone	54.0	87.1	76.9	12	1.181	1.8 × 10^−3	0.504	12.64	12.84	48.8
15 coal roof shale	56.6	45.4	34.3	6	0.553	1.9 × 10^−3	0.504	4.63	5.60	34.7