Experimental Study on the Soil Conditioning Materials for EPB Shield Tunneling in Silty Sand

Table 3

Scheme of orthogonal test.

No.	Concentration of foam solution (A) (%)		Air pressure (B) (MPa)		Air flow (C) (L/min)		Liquid pressure (D) (MPa)		Liquid flow (E) (ml/min)
	Level	Value	Level	Value	Level	Value	Level	Value	Level	Value
1	1	2.0	2	0.3	3	3.0	2	0.3	3	150
2	3	4.0	4	0.5	1	1.0	2	0.3	2	100
3	2	3.0	4	0.5	3	3.0	3	0.4	4	200
4	4	5.0	2	0.3	1	1.0	3	0.4	1	50
5	1	2.0	3	0.4	1	1.0	4	0.5	4	200
6	3	4.0	1	0.2	3	3.0	4	0.5	1	50
7	2	3.0	1	0.2	1	1.0	1	0.2	3	150
8	4	5.0	3	0.4	3	3.0	1	0.2	2	100
9	1	2.0	1	0.2	4	4.0	3	0.4	2	100
10	3	4.0	3	0.4	2	2.0	3	0.4	3	150
11	2	3.0	3	0.4	4	4.0	2	0.3	1	50
12	4	5.0	1	0.2	2	2.0	2	0.3	4	200
13	1	2.0	4	0.5	2	2.0	1	0.2	1	50
14	3	4.0	2	0.3	4	4.0	1	0.2	4	200
15	2	3.0	2	0.3	2	2.0	4	0.5	2	100
16	4	5.0	4	0.5	4	4.0	4	0.5	3	150