Corrosion Behavior and Failure Mechanism of Prestressed Rock Bolts (Cables) in the Underground Coal Mine

Table 1

The details of bolt (cable) samples.

Sample	Bolt diameter (mm)	Service period (year)	Residual prestress (%)	Working environment					Sample morphological description
				Surrounding rock	Temperature	Humidity	Seepage water pH	Harmful ions
S-1	20	1.5	≥70	Coal	25.2	93.6	7.1	SO4^2−, Cl^−	Greenish brown and slightly uniform corroded, no failure
S-2	20	2.0	≥70	Coal	24.9	90.8	7.4	SO4^2−, Cl^−	Greenish brown and slightly uniform corroded, no failure
S-3	20	3.0	≥70	Coal	25.6	91.5	7.5	SO4^2−, Cl^−	Greenish brown and slightly pitting corroded, no failure
S-4	20	5.0	≥70	Coal	24.8	93.2	7.2	SO4^2−, Cl^−	Reddish brown and severe pitting corroded, no failure
S-5	20	8.0	≥70	Coal	25.2	92.9	7.4	SO4^2−, Cl^−	Reddish brown and severe pitting corroded, no failure
S-6	16	6.0	≥70	Coal	24.9	93.3	7.6	SO4^2−, Cl^−	Reddish brown and severe pitting corroded, failure