Research Article
Study on Pressure Relief Technology of High-Pressure Water Jet of Residual Coal Pillar in Overlying Goaf in Close Seam Mining
Table 3
Physical and mechanical parameters of the model.
| | Rock stratum | Density (kg/m3) | Bulk modulus (GPa) | Shear modulus (GPa) | Tensile strength (MPa) | Cohesion (MPa) | Internal friction angle (°) | Thickness (m) |
| | Coal | 1410 | 2.1 | 1.3 | 1.50 | 1.76 | 22.00 | 6 |
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