Construction Technical Requirements of Self Drilling Anchor
1. Technical points of arranging self drilling anchor.
Generally, constructors arrange self drilling anchor according to quite bigger angle between radial pattern tunnel section and main structural surface. When encountering imapparent main structural surface, constructors can arrange self drilling anchor vertical with tunnel surrounding contour and quincunx pattern on excavation surface.
2. Location of self drilling anchor hole.
Generally, error is not more than 4-10cm. After drilling, high pressure water should wash hole and clean it. Then water should be blew out of hole and evaporated.
As for machinery anchoring hole, depth error should be controlled between -1 and 1cm. When drilling to designed depth, encountering broken stratum or quite soft rock, location and depth of self drilling anchor bolt should be changed.
3. Construction process of self drilling anchor supporting.
Technicians should ensure that self drilling anchor bolt is perfectly straight without defect and impurity. At the same time, rust should not be stayed on surface of anchor bar. Otherwise, they will influence whole quality of construction.
4. Installation technical requirement.
When installing self drilling anchor, function of drilling, grouting and anchoring is generally carried out at the same time. Seriflux should be ensured to flow out from bottom and full until pure seriflux flowing out. Otherwise, it will cause bad anchoring effect.