Research Article
Numerical Assessment on Unloading Disturbance and Gas Extraction in Remote Distance Protective Layer Mining
Table 2
Physicomechanical parameters for each rock layer.
| | Rock formation | Elasticity moduli (GPa) | Tensile strength (MPa) | Cohesion (MPa) | Friction angle (°) | Poisson’s ratio | Density (kg/m3) |
| | Overlying strata | 2.2 | 2.7 | 6.6 | 37 | 0.20 | 1900 | | Siltstone | 5.0 | 5.4 | 6.2 | 40 | 0.25 | 2500 | | Sandy mudstone | 3.0 | 3.5 | 3.7 | 32 | 0.23 | 2530 | | Claystone | 1.8 | 1.1 | 3.0 | 32 | 0.20 | 1900 | | Mudstone | 2.0 | 2.5 | 2.7 | 30 | 0.18 | 2430 | | Coal seam | 1.0 | 1.0 | 2.0 | 28 | 0.21 | 1300 | | Kaolinite rock | 1.8 | 2.5 | 4.0 | 35 | 0.24 | 2400 | | Lower strata | 3.0 | 2.0 | 4.6 | 40 | 0.25 | 2500 |
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