Research Article
Study on Dynamic Evolution of Roof Crack and Support Timing of Secondary Tunneling for Large Section Open-Off Cut in Deep Mines
Table 1
Intact rock properties and calculated rock mass properties.
| | Rock strata | Intact rock | RQD | Rock mass | | (GPa) | (MPa) | (MPa) | (GPa) | (MPa) | (MPa) |
| | Sandy mudstone | 5.89 | 11.44 | 1.14 | 90 | 3.42 | 8.12 | 0.81 |
| | Fine sandstone | 8.53 | 13.88 | 1.40 | 92 | 5.40 | 10.41 | 1.05 |
| | Coal | 1.48 | 4.99 | 0.50 | 88 | 0.79 | 3.36 | 0.34 |
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