Research Article
An Evaluation Method of Rock Brittleness Based on the Prepeak Crack Initiation and Postpeak Stress Drop Characteristics
Table 4
Classification and description of brittleness index B1.
| Grade | B1 | Description |
| 1 | 1 | M⟶−∞, ideal brittleness | 2 | 0.6321∼1 | −∞ < M < − E, high brittleness | 3 | 0.6321 | M = − E | 4 | 0∼0.6321 | −E < M < 0, low brittleness | 5 | 0 | M = 0, ideal plasticity | 6 | <0 | M > 0, strain hardening |
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