A Study of Acoustic Emission and Damage Evolution of Limestone under Different Stress Paths and Confining Pressures

Table 2

Statistic results of original rock stress in some underground engineering in China (with the downdip angle as positive) [19–21].

Number	Project	Buried depth	Maximum principal stress			Intermediate principal stress			Minimum principal stress			Equivalent confining pressure
			Value (MPa)	Azimuth (°)	Plunge (°)	Value (MPa)	Azimuth (°)	Plunge (°)	Value (MPa)	Azimuth (°)	Plunge (°)	Value (MPa)
1	Hebi Six Mine	447.66	32.50	258.07	12.35	22.16	101.54	75.56	4.07	349.21	5.19	5.47
2	Jiaozuo Jiulishan Mine	318.70	8.85	357.59	74.80	5.70	192.08	14.53	1.06	101.12	8.9	5.60
3	Lianshao Niumasi Mine	556.57	21.78	87.99	18.56	17.43	282.23	70.89	1.86	170.46	4.38	5.31
4	Beipiao Guanshan Mine	989.05	52.96	34.79	11.25	30.85	148.24	63.45	13.23	299.77	23.71	6.57
5	Xinwen Suncun Mine	870	38.13	100.1	24.2	28.35	79.2	61.5	1.61	14.8	14.1	14.27
6	Jinping II Hydropower Station Tunnel	169	10.9	157	-3	7.2	70	50	6.5	64	-40	9.59
7		169	12.5	139	-18	11.1	39	-29	7.9	77	55	13.57
8		259	16.79	106	-11.04	10.9	23	-27.6	8.9	35.5	59.9	14.05
9		317	11.11	126	-24	7.7	1	-52	5.17	50	27	8.51
10		616	19.11	148	58	9.97	326	31	7.19	56	1	11.17
11		1079	40.69	146	49	18.81	75	-16	12.82	177	-36	18.88