Research Article
Spatial and Temporal Distribution Law and Influencing Factors of the Mining-Induced Deformation and Failure of Gas Boreholes
Table 2
Mechanical parameters of strata.
| | Lithology | | Coal | Mudstone | Siltstone | Sandstone |
| Strength parameters | Matrix | Peak value | Internal friction (°) | 29 | 35 | 45 | 50 | Cohesion (MPa) | 1.06 | 1.9 | 2.2 | 2.8 | Tensile strength (MPa) | 0.03 | 0.42 | 0.68 | 1 | Residual value | Internal friction (°) | 28 | 34 | 43 | 48 | Cohesion (MPa) | 0.0106 | 0.19 | 0.22 | 0.28 | Tensile strength (MPa) | 0 | 0 | 0 | 0 | Joint | Peak value | Internal friction (°) | 25 | 30 | 42 | 45 | Cohesion (MPa) | 0.8 | 1.5 | 2 | 2.5 | Tensile strength (MPa) | 0.01 | 0.4 | 0.6 | 0.8 | Residual value | Internal friction (°) | 24 | 29 | 38 | 43 | Cohesion (MPa) | 0.008 | 0.15 | 0.2 | 0.25 | Tensile strength (MPa) | 0 | 0 | 0 | 0 |
| Stiffness parameters | | Bulk modulus (GPa) | 1.5 | 3.5 | 3.6 | 5.3 | | Shear modulus (GPa) | 0.3 | 1.6 | 2.2 | 4 |
|
|