Abstract：The corrosion environment of an underground drift of one coal mine and the corrosion status of in-situ split-set bolts，which are embedded in the drift for 10 years，have been investigated. The content of the corrosive mass in the underground water，the general mass loss and the local pit corrosion situation of the bolts are tested. The tensile test is carried out to analyze the peak bearing capacity and the plastic behavior. The obtained results are as follows：the corrosion of the split-set bolts without any protection is very serious，and most of the investigated specimens are nearly out of service. The outer corrosion of the bolts is mainly pit corrosion，and the inner corrosion is nearly uniform corrosion. The pit corrosion amount，area，and depth，etc. all follow certain scatter law；moreover，there is an inherent connection between the pitting area and the pitting depth. The pitting corrosion and punches on the bolt surface have great impairment on the mechanical behaviors of bolts. The loss ratio of the elongation percentage of the bolts is much greater than that of the peak bearing capacity，which shows that the impairment of the corrosion on the plasticity of the bolts is more server than that on the bearing capacity of the bolts. Therefore，the deformation of the bolt before its failure is difficulty to be monitored，and emergent hazards will easily happen.
