Research Article
The Study of Key Stratum Location and Characteristics on the Mining of Extremely Thick Coal Seam under Goaf
Table 1
The mechanical parameters of rock masses.
| | Lithology | Density (kg·m3) | Bulk modulus (GPa) | Shear elasticity (GPa) | Cohesion (MPa) | Internal friction angle (°) | Strength of extension (MPa) |
| | Packsand | 2600 | 27.1 | 7.0 | 27.1 | 27.0 | 3.2 | | Medium-grained sandstone | 2300 | 26.7 | 7.0 | 27.1 | 27.0 | 3.2 | | Argillaceous sandstone | 1800 | 26.7 | 6.0 | 26.2 | 25.2 | 1.2 | | No. 8 coal seam | 1300 | 9.2 | 8.0 | 3.2 | 24.2 | 1.5 | | Medium-grained sandstone | 2350 | 26.7 | 7.0 | 27.1 | 27.0 | 3.2 | | Argillaceous sandstone | 1800 | 20.6 | 7.0 | 6.5 | 18.5 | 1.5 | | Mudstone | 1500 | 18.1 | 5.0 | 6.5 | 16.5 | 1.2 | | No. 13 coal seam | 1300 | 9.2 | 8.0 | 3.2 | 24.2 | 1.2 | | Sandstone | 2400 | 26.7 | 7.0 | 27.2 | 27.0 | 3.5 |
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