Research Article
Field and Numerical Investigation on the Coal Pillar Instability of Gob-Side Entry in Gently Inclined Coal Seam
Table 1
Numerical simulation parameters.
| | Rock layer | Rock type | Average thickness (m) | Density (kg/m3) | Bulk modulus (GPa) | Shear modulus (GPa) | Tensile strength (MPa) | Internal stress (MPa) | Internal friction angle (°) |
| | Overlying strata | — | 385 | 2500 | 12.00 | 7.8 | 1.6 | 2.4 | 28 | | Main roof | Middle-fine sandstone | 4.83 | 2680 | 12.23 | 8.4 | 2.19 | 9.1 | 36 | | Immediate roof | Sandy mudstone | 3.3 | 2659 | 2.51 | 1.36 | 1.70 | 1.9 | 21 | | Coal | — | 3 | 1212 | 0.79 | 0.24 | 1.52 | 3.46 | 22 | | Immediate floor | Sandy mudstone | 2.76 | 2659 | 2.51 | 1.36 | 1.70 | 1.9 | 21 | | Main floor | Middle-fine sandstone | 20.04 | 2680 | 12.23 | 8.4 | 2.19 | 9.1 | 36 |
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