The service life of rock bolt embedded in the rock and soil depends on the durability of the rock bolt. Factors that affect the durability of the rock bolt with prestressed large tonnage, improper material, construction technology and environment corrosion, and the biggest threat is from corrosion. Therefore, the durability of the rock bolt and the damage degree of rock bolt corrosion resistance has a direct relationship.
The main factors influencing the bolt corrosion:
Environmental factors: Rock bolt directly contact with the air, water and soil (rock) in the soil, the pH of this three-phase medium, aggressive ions and gas concentration and recharge exchange speed will directly affect the corrosion rate.
Material factors: It mainly involves the problem of rock bolt material selection; the rock bolt steel products should be preferred quality with stable, uniform material, fewer impurities.
Construction factors: The uniform degree of anchorage bond body has a decisive effect on corrosion of rock bolt. Therefore, the construction of the stand must be done so that making the protective layer uniform, forming a complete bond, lest appearing uneven especially discontinuous phenomenon.
The rock bolt anticorrosion measures:
1. The type of protection and standards should be determined by the lifespan of rock bolt, the degree of rock bolt corrosion in the environment and rock bolt damage consequences.
2. The validity of the rock bolt protection shall be equal to the period of validity of rock bolt;
3. Rock bolt in all its free length must be able to move freely, when anchor test and load, all load can be found by the free to the anchoring segment transmission;
4. Rock bolt protective facilities must have enough strength and toughness, without damage when anchor load;