Corrosion Investigation of Rock Anchors Served over 10 Years in Underground Powerhouse of a Hydropower Station

Table 11

Combined ratings of anchor heads structure.

Combined rating	Position					Total	Percent (%)
	Upstream end wall	Downstream end wall	Left-end wall	Right-end wall	Arch crown
A0	5	5	3	2	3	18	11.69
B1	0	0	0	0	0	0	0.00
B2	10	5	2	4	41	62	40.26
B3	0	0	0	0	16	16	10.39
B4	4	7	0	0	16	27	17.53
C1	1	0	0	1	0	2	1.30
C2	1	6	2	0	5	14	9.09
C3	0	0	0	1	0	1	0.65
C4	5	1	0	1	0	7	4.55
D1	0	2	0	0	0	2	1.30
D2	0	1	1	0	0	2	1.30
D3	0	0	0	0	0	0	0.00
D4	1	1	0	1	0	3	1.95