Rock bolts made of different types of steel have been widely used for the reinforcement of jointed rock slopes, nuclear waste repositories, underground mines and tunnels.Rock bolts are often exposed to corrosive environments such as chloride and sulfate ions,moisture, fluctuating temperature, and potential seepage of water through the fractures or joints in the rock .A survey of rock bolt failures indicated that the life of a rock bolt is mainly controlled by corrosion which largely affects the unbonded free length.
The causes of failure of an anchored rock slope are often difficult to characterize because imperfections in installation, corrosion protection, and workmanship on rock anchorage system may induce failure either individually or in combination. In this article, however,the corrosion of rock bolt is taken as the sole cause of possible failure of the anchored rock slope. As reported in the literature, some geotechnical engineering accidents were caused by performance degradation or failure of the anchorage system due to the corrosion effects.
Sinorock develops the duplex coating rock bolt for avoiding corrosion, there are two corrosion-prevention measurements on the bolt surface: epoxy coating and hot-dip galvanizing.
Epoxy coating: an epoxy resin coating material, which is acid-resisting and solidified at room temperature.Hot-dip galvanizing: a method that anchor bar gains metallic coating by immersing into molten galvanizing zinc.