Table 2 Physical and mechanical parameters of each layer.
Serial number | Lithology | Thickness/m | Burial depth/m | Density/kg m−3 | Compressive strength/MPa | Tensile strength/MPa | Notes |
|---|---|---|---|---|---|---|---|
1 | Cover layer | 23.5 | 23.5 | 2250 | – | – |  |
2 | Fine sandstone | 4 | 27.5 | 2595 | 51.3 | 3.2 | Â |
3 | Sandy mudstone | 4.5 | 32 | 2550 | 33.5 | 1.3 | Â |
4 | Siltstone | 9 | 41 | 2650 | 54.9 | 3.0 | Scheme II |
5 | Sandy mudstone | 9 | 50 | 2550 | 34.9 | 1.1 | Â |
6 | Medium sandstone | 9 | 59 | 2500 | 45.2 | 2.3 | Scheme I |
7 | Sandy mudstone | 3.5 | 62.5 | 2550 | 32.5 | 1.5 | Â |
8 | 4# coal seam | 4 | 66 | 1450 | 14.6 | 1.32 | Â |
9 | Sandy mudstone | 13 | 79 | 2550 | 28.9 | 1.3 | Â |
10 | 5# coal seam | 4 | 83 | 1450 | 14.2 | 1.32 | Â |
11 | Sandy mudstone | 8 | 91 | 2550 | 32.5 | 1.5 | Â |
12 | Fine sandstone | 4.5 | 95.5 | 2595 | 58.4 | 3.0 | Â |
13 | Sandy mudstone | 9 | 104.5 | 2550 | 34.9 | 4.1 | Â |
14 | 6# coal seam | 12 | 116.5 | 1450 | 16.1 | 1.3 | Â |
