Gob-Side Entry Retaining Technology with Advanced Empty Hole Butterfly-Shaped Weakening in Three-Soft Coal Seam in China

Table 3

Orthogonal test table of stress interference factors.

Scheme	Factor 1 (MPa)	Factor 2 η	Factor 3 D (cm)	Factor 4 L/D	σ1 (MPa)	σ2 (MPa)	(%)	1	2
1				3.0	1.84		3.95	4.60	4.43
2	1	1	1	3.5	1.83	1.77	3.39	4.58	4.43
3				4.0	1.82		2.82	4.55	4.43
4			1		1.84	1.77	3.95	4.60	4.43
5	1	1	4	3.0	1.85	1.78	3.93	4.63	4.45
6			6		1.86	1.79	3.91	4.65	4.48
7	1	1			1.85	1.78	3.93	4.63	4.45
8		3	4	3.0	7.16	7.06	1.42	3.75	3.70
9		5			12.5	12.3	1.63	4.01	3.95
10	1				7.11	7.03	1.14	3.72	3.68
11	2	3	2	3.0	14.2	14.1	0.71	3.72	3.69
12	3				21.3	21.1	0.95	3.72	3.69