Theoretical and Numerical Research on V-Cut Parameters and Auxiliary Cuthole Criterion in Tunnelling

Table 2

The critical depth of the four types of rocks with auxiliary cut holes.

Inclination angle (°)	Shale (m)	Sandstone (m)	Limestone (m)	Granite (m)
40	5.73	3.83	3.11	2.78
45	5.57	3.68	3.01	2.68
50	5.37	3.48	2.88	2.54
55	5.11	3.24	2.72	2.37
60	4.77	2.91	2.50	2.15
65	4.31	2.47	2.21	1.84
70	3.65	1.95	1.80	1.40
75	2.59	1.76	1.50	0.90

The critical hole depths in the table are calculated under the condition that the 2# rock emulsion explosive is used in four kinds of rocks.