A New Method for Predicting Residual Strength of Rock in Water Diversion Tunnel Using Drilling Process Monitoring

Table 2

Summary of the calculated contact friction coefficient at the different rake angles.

No.	Rock types	φ' (°)	a = 5°		a = 10°		a = 15°		a = 20°
			θ (°)	tanθ	θ (°)	tanθ	θ (°)	tanθ	θ (°)	tanθ
1	Amarelo Pais granite	67.98	63.52	2.01	58.73	1.65	53.64	1.36	48.24	1.12
2	Blanco Mera granite	69.45	64.91	2.14	60.07	1.74	54.94	1.43	49.52	1.17
3	Vilachan granite	65.89	61.54	1.85	56.85	1.53	51.82	1.27	46.45	1.05
4	Blanco Mera granite	70.09	65.51	2.20	60.65	1.78	55.51	1.46	50.08	1.19
5	Stanstead granite	64.52	60.25	1.75	55.62	1.46	50.64	1.22	45.30	1.01
6	Bunt sandstone	46.24	41.40	0.88	38.05	0.78	34.13	0.68	29.69	0.57
7	Indiana limestone buff	33.79	38.17	0.79	35.08	0.70	31.41	0.61	27.17	0.51
8	Red sandstone	45.46	43.69	0.96	40.15	0.84	36.07	0.73	31.48	0.61
9	Gosford sandstone	53.04	49.57	1.17	45.59	1.02	41.13	0.87	36.22	0.73
10	Carrara marble	51.56	46.94	1.07	43.15	0.94	38.86	0.81	34.09	0.68
11	Westerly granite	72.90	68.21	2.50	63.26	1.98	58.06	1.60	52.61	1.31
12	Rhyolite	21.66	39.17	0.81	36.00	0.73	32.24	0.63	27.94	0.53
13	Indiana limestone gray	51.03	41.68	0.89	38.30	0.79	34.37	0.68	29.90	0.58
14	Porphyry	50.50	47.23	1.08	43.42	0.95	39.11	0.81	34.32	0.68
15	Rajnagar marble	48.44	45.33	1.01	41.67	0.89	37.48	0.77	32.80	0.64
16	Biotite chlorite schist	44.17	45.63	1.02	41.94	0.90	37.73	0.77	33.03	0.65
17	Purulia gneiss	62.95	58.78	1.65	54.22	1.39	49.29	1.16	44.00	0.97
18	Kirthai granite gneiss	64.44	60.18	1.74	55.55	1.46	50.57	1.22	45.24	1.01
19	Tennessee sandstone	26.51	42.25	0.91	38.82	0.80	34.85	0.70	30.35	0.59
20	Coal	42.19	43.27	0.94	39.77	0.83	35.72	0.72	31.16	0.60
21	Sandstone	63.54	59.44	1.69	54.85	1.42	49.90	1.19	44.59	0.99
22	Norite	65.96	60.09	1.74	55.46	1.45	50.48	1.21	45.16	1.01
23	Quartzite	75.57	70.77	2.87	65.76	2.22	60.53	1.77	55.08	1.43
24	Hejiata coal G1	50.61	47.33	1.08	43.51	0.95	39.19	0.82	34.40	0.68
25	Hejiata coal G2	56.96	53.20	1.34	48.97	1.15	44.30	0.98	39.22	0.82
26	Coarse marble	39.85	42.97	0.93	39.49	0.82	35.46	0.71	30.92	0.60
27	Medium marble	47.07	44.08	0.97	40.51	0.85	36.41	0.74	31.80	0.62
28	Sandstone	48.13	42.64	0.92	39.19	0.82	35.18	0.70	30.66	0.59