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

Table 3

Groundwater aggressivity in the underground main powerhouse.

Item	Time (year)	Test value	Standard value	Description
HCO3^−	2018	2.61 mmol/L	＞1.07 mmol/L	No dissolution corrosion
	2019	2.59 mmol/L
pH	2018	8.25	＞6.5	No general acidic corrosion
	2019	8.28
Mg^2+	2018	25.34 mg/L	＜1000 mg/L	No magnesium sulfate corrosion
	2019	50.60 mg/L
SO4^2−	2018	61.0 mg/L	＜250 mg/L	No magnesium sulfate corrosion
	2019	49.4 mg/L
Cl^−	2018	22.48 mg/L	＜100 mg/L	Slight corrosion
	2019	18.80 mg/L