Research Article
Macro-Micro Response Characteristics of Surrounding Rock and Overlying Strata towards the Transition from Open-Pit to Underground Mining
Table 2
The final PFC mesoparameters of the rock samples.
| Rock type | Parallel bond modulus (gPa) | Cohesion (kPa) | Tension (kPa) | Friction (°) | Stiffness ratio | Density (kg/cm3) |
| Quaternary clay | 0.17 | 7.37 | 7.37 | 18.2 | 2.1 | 1458 | Dark gray cryptocrystalline dolomite | 0.19 | 8.42 | 8.42 | 30.20 | 2.1 | 2089 | Off-white coarse-grained dolomite | 0.21 | 7.04 | 7.04 | 29.66 | 2.1 | 2090 | Muddy quartz sandstone | 0.16 | 7.04 | 7.04 | 29.52 | 2.1 | 2122 | Phosphate strata | 0.23 | 10.14 | 10.14 | 30.53 | 2.1 | 2155 | Layered muddy dolomite | 0.24 | 13.44 | 13.44 | 30.17 | 2.1 | 2122 | Muddy dolomite | 0.25 | 11.32 | 11.32 | 33.23 | 2.1 | 2065 | Boundary phosphate strata | 0.26 | 11.81 | 11.81 | 30.89 | 2.1 | 2078 | Off-white layered dolomite | 0.29 | 21.86 | 21.86 | 47.23 | 2.1 | 2025 | Dark gray layered dolomite | 0.26 | 22.67 | 22.67 | 30.17 | 2.1 | 2125 |
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Note: the minimum particle radius is , and the particle size ratio is 1.5. |