Research Article
Study on the Migration Law of Overlying Strata of Gob-Side Entry Retaining Formed by Roof Cutting and Pressure Releasing in the Shallow Seam
Table 1
Rock layer mechanical parameters.
| Strata | Thickness (m) | Internal friction angle (°) | Density (g · cm−3) | Tensile strength (MPa) | Elasticity modulus (GPa) | Poisson’s ratio |
| Siltstone | 4.0 | 30 | 2.552 | 2.80 | 32 | 0.28 | Fine sandstone | 4.0 | 30 | 2.550 | 2.80 | 32 | 0.28 | Mudstone | 1.0 | 30 | 2.301 | 3.53 | 23 | 0.28 | 12 upper coal | 2.0 | 30 | 1.462 | 0.60 | 15 | 0.35 | Siltstone | 2.0 | 30 | 2.511 | 2.30 | 35 | 0.25 | Siltstone | 4.0 | 30 | 2.550 | 2.80 | 32 | 0.28 | Fine sandstone | 4.0 | 30 | 2.514 | 2.30 | 35 | 0.25 |
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