Relationship between Brittleness Index and Crack Initiation Stress Ratio for Different Rock Types

Table 4

Percentage of K value range distribution of different rock types under three prediction methods.

Method	Percentage of K value range distribution of igneous rock (%)			Percentage of K value range distribution of metamorphic rock (%)			Percentage of K value range distribution of sedimentary rock (%)
	0.2∼0.4	0.4∼0.6	0.6∼0.8	0.2∼0.4	0.4∼0.6	0.6∼0.8	0.2∼0.4	0.4∼0.6	0.6∼0.8
1	8.6	53.4	31	42.9	28.6	19	50	35.4	2.1
2	13.8	60.3	22.4	42.9	33.3	23.8	6.25	29.2	47.9
3	15.5	58.6	22.4	47.6	33.3	19	6.25	29.2	47.9