Research Article
Influence Law of Interbedded Strata and Their Collapse on the Mining of Extremely Thick Coal Seam under Goaf
Table 3
The mechanical parameters of the contact surface of coal and rock.
| | Lithology | Normal stiffness (GPa) | Shear stiffness (GPa) | Cohesion (MPa) | Internal friction angle (°) | Strength of extension (MPa) |
| | Pack sand | 8.5 | 8.5 | 1.6 | 20.2 | 0 | | Medium-grained sandstone | 7.0 | 7.0 | 1.5 | 19.5 | 0 | | Argillaceous sandstone | 6.0 | 6.0 | 0 | 14.5 | 0 | | No. 8 coal seam | 5.5 | 5.5 | 0 | 13.5 | 0 | | Medium-grained sandstone | 8.5 | 8.5 | 1.5 | 20.2 | 0 | | Argillaceous sandstone | 7.5 | 7.5 | 1.0 | 19.5 | 0 | | Mudstone | 6.0 | 6.0 | 0 | 14.5 | 0 | | No. 13 coal seam | 5.5 | 5.5 | 0 | 13.5 | 0 | | Sandstone | 8.5 | 8.5 | 1.5 | 20.2 | 0 |
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