Research Article
Influence of Valleys Terrain on Pressure of Fully Mechanized Working Faces in Shallow Coal Seams
Table 6
Parameters of the numerical model of rock strata.
| | Stratum | Thickness (cm) | Volume-weight (KN/m3) | Bulk modulus (GPa) | Shear modulus (GPa) | Internal friction angle | Tensile strength (MPa) | Cohesive strength (MPa) | Model unit volume (m2) |
| | Unconsolidated formation | 34 | 25 | 14 | 8 | 30 | 1.3 | 2.5 | | | Main key stratum | 8 | 28 | 32 | 20 | 36 | 2.4 | 4.9 | 14 × 8 | | Sandy mudstone | 15 | 26 | 10 | 5 | 24 | 1.1 | 2.2 | 5 × 3 | | Subcritical strata 1 | 5 | 28 | 19 | 14 | 28 | 1.6 | 3.8 | 10 × 6 | | 1−2 upper coal immediate roof | 9 | 25 | 10 | 5 | 24 | 1.1 | 2.2 | 3 × 3 | | 1−2 upper coal seam | 3.5 | 14 | 6 | 4 | 22 | 0.8 | 1.8 | 5 × 4.5 | | Subcritical strata 2 | 5 | 28 | 19 | 14 | 28 | 1.6 | 3.8 | 10 × 6 | | 1−2 coal immediate roof | 6 | 25 | 10 | 5 | 24 | 1.1 | 2.2 | 3 × 3.5 | | 1−2 coal seam | 4.5 | 14 | 6 | 4 | 22 | 0.8 | 1.8 | 5 × 3.5 | | Bottom plate | 15 | 28 | 19 | 14 | 28 | 1.6 | 3.8 | |
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