1, Metal surface composition changes in local area and produce different potential difference, which leading to corrosion.
2, Metal internal uneven or metal loading charge caused the metal oxide film fracture on the surface, occurs the corrosion phenomenon on the rupture condition.Concentration of oxygen in the soil is different, so that different polarity in different parts, causing corrosion.
3,Ion concentration changes in the geological environment , which also makes the body of self drilling anchor system produce batteries, lead to corrosion.
The following describes the corrosion protection measures of self drilling anchor system:
1) When selecting materials, should be preferred to choose reliable quality, good toughness and does not easily affected by stress and hydrogen embrittlement of low carbon steel;
2) When installing self drilling anchor, avoid dry-wet alternate environment, and take the drainage system, reduce the corrosion speed;
3)In the construction process, control the water cement ratio and cement slurry concentration, the cracks of cement barrier should less than 0.1 mm, improve the anchor solid density and penetration resistance.
4) If it is used in permanent construction environment,which can be adopted by galvanized or epoxy coating to handle this kind of cases, (should be avoided abrasion during transport or installation on the coating wear).
