Research Article
Experimental Investigation on the Propagation of Hydraulic Fractures through Coal-Rock Interfaces
Table 2
Hydraulic fracturing simulation experimental program on combination samples.
| Combination sample | Sample no. | Fracture initiation position | Raw coal-rock size/mm | Stress/MPa | Triaxial pressure diagram | Length × width × thickness | | | |
| Two-dimensional coal-rock combination plate | 1# | Concrete | 208 × 102 × 49 | 3.5 | 4 | 2 | | 2# | Concrete | 210 × 100 × 50 | 3.5 | 4 | 2 | 4# | Concrete | 195 × 95 × 50 | 3.5 | 4 | 2 |
| Large-scale cubic coal and rock mass | 1# | Sand mudstone | 270 × 135 × 150 | 4.7 | 6.8 | 2.8 | | 3# | Coal | 220 × 100 × 200 | 4.7 | 6.8 | 2.8 | 4# | Sand mudstone | 270 × 172 × 158 270 × 170 × 75 (coal) | 4.7 | 6.8 | 2.8 |
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