The Key Stratum Structure Morphology of Longwall Mechanized Top Coal Caving Mining in Extra-Thick Coal Seams: A Typical Case Study
Table 1
The mechanical parameters of blocks and contacts.
Lithology
Block properties
Contact properties
Density (kg/m3)
K (GPa)
G (GPa)
Cb (MPa)
φb (°)
σtb (MPa)
kn (GPa/m)
ks (GPa/m)
Cj (MPa)
φj (°)
σtj (MPa)
Siltstone
2538
6.36
3.28
4.0
33
4.3
2640
1120
0.8
11
2.1
Sandy mudstone
2506
9.4
3.0
3.75
30
3.7
2564
1049
0.75
10
1.8
Medium sandstone
2524
14.3
3.7
4.8
37
4.5
2940
1520
0.96
16
2.2
Mudstone
2500
2.5
1.4
3.15
26
3.1
1790
1128
0.63
8
1.5
Coal
1400
1.1
0.95
2.0
28
2.2
1586
528
0.4
9
1.1
Fine sandstone
2550
10.6
3.5
4.5
35
4.3
2740
1320
0.9
13
2.05
K is the bulk modulus of blocks; G is the shear modulus of blocks; Ci is the cohesion; φi is the friction angle; σti is the tensile strength; kn is the normal stiffness of contacts; ks is the shear stiffness of contacts.
