Research Article
Influence of Three-Dimensional Stress Field Variation on Fracture Evolution Characteristics of a Roof
Table 1
Mechanical parameters of coal seam and rock strata.
| | Stratum | Lithology | Thickness (m) | Elastic modulus (GPa) | Poisson ratio | Density (kg/m3) | Internal friction angle (°) | Initial cohesion (MPa) | Residual cohesion (MPa) |
| | Roof | Sandstone | 110 | 15 | 0.3 | 2560 | 25 | 3 | 2 | | Mudstone | 2 | 8 | 0.35 | 2480 | 18 | 1.2 | 1 | | Middle-fine sandstone | 20 | 9 | 0.3 | 2560 | 24 | 1.3 | 1.1 | | Argillaceous siltstone | 3 | 8 | 0.36 | 2480 | 18 | 1.1 | 0.8 | | Coal seam | 3# coal | 8.5 | 7 | 0.35 | 1400 | 16 | 1 | 0.6 | | Floor | Siltstone | 4 | 8 | 0.35 | 2560 | 18 | 1.1 | 0.8 | | Fine sandstone | 32.5 | 12 | 0.3 | 2560 | 30 | 5 | 4 |
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