Failure Characteristics and Confined Permeability of an Inclined Coal Seam Floor in Fluid-Solid Coupling
Table 1
Physical and mechanical parameters of the roof and floor strata of the 1066 inclined coal seam workface.
Number
Lithology
Thickness (m)
Density (kg·m−3)
Bulk modulus (GPa)
Shear modulus (GPa)
Tensile strength (MPa)
Cohesion (MPa)
Internal friction angle (°)
Permeability coefficient (m·s−1)
Porosity
1
Medium sandstone
14.0
2650
2.78
2.63
0.95
3.90
41
0.8e − 12
0.12
2
Mudstone
9.5
2620
1.86
0.53
0.50
2.70
30
0.8e − 13
0.08
3
Medium sandstone
4.0
2650
2.78
2.63
0.95
3.90
41
0.8e − 12
0.12
4
Siltstone
7.5
2650
4.54
4.30
1.20
4.90
40
7e − 12
0.14
5
Fine sandstone
5.0
2650
3.38
3.32
1.10
5.10
42
5e − 12
0.14
6
10-coal
3.4
1400
1.43
1.09
0.03
1.00
25
1e − 12
0.15
7
Siltstone
6.0
2650
4.54
4.30
1.20
4.90
40
7e − 12
0.13
8
Fine sandstone
9.0
2650
3.38
3.32
1.50
3.50
38
5e − 12
0.13
9
Sand mudstone
6.5
2600
1.73
1.09
0.65
2.90
25
0.6e − 13
0.09
10
Medium sandstone
12.0
2650
2.78
2.63
0.95
3.90
41
0.8e − 12
0.12
11
Sand mudstone
9.0
2600
1.73
1.09
0.65
2.90
25
0.6e − 13
0.09
12
Medium sandstone
3.0
2650
2.78
2.63
0.95
3.90
41
0.8e − 12
0.12
13
Siltstone
5.5
2650
4.54
4.30
1.20
4.90
40
0.5e − 12
0.14
14
Medium sandstone
2.0
2650
2.78
2.63
0.95
3.90
41
0.8e − 12
0.12
15
Aquifer
90.0
2500
4.20
3.12
1.40
3.20
38
5e − 10
0.31
Note. The unit of permeability coefficient in FLAC3D software is different from that in hydraulics, and their conversion relation is K (m2/Pa·s) = K (cm/s) × 1.02 × 10−6.
