1.
Strong applicability
Self-drilling anchor bolt has strong applicability, especially in the weak surrounding rock. Self-drilling anchor bolt can combine drilling and anchoring together. Its hollow bar can also be regarded as a grouting gallery from inside to outside. It doesn’t need pore-forming and casing pipe to protect wall at a backfilled region, decomposed rock, broken rock, sand layer, clay layer, pebble bed and other weak surrounding rock.
2.
Pressure grouting method
Grouting is from the bottom, which can realize pressure grouting. It should be controlled according to design value. Pressure maintenance should not be less than 10 min when grouting at orifices. Pressure grouting can rapidly make slurry fully permeate into cracks of rock and soil. After slurry diffusion and concretion into integrity, which can reach the purpose of permanent anchoring surrounding rocks.
3.
Simple and fast for construction
Continuous international screw thread and coupler make the process, installation and lengthening of
self-drilling anchor bolt simple and fast for operation. After drilling to designed depth, it can instantly realize borehole cleaning, pressure grouting and self-drilling anchor bolt don’t need to be pulled out. Compared with a common hollow anchor bolt and common mortar anchor bolt, its construction process is simple and benefit is obvious.
4.
Lengthened to reinforce in narrow space
Continuous screw thread can make self-drilling rock bar be cut and connected arbitrarily. In narrow space, it can realize reinforcement of dangerous rock. At the same time, continuous screw thread of self-drilling anchor bolt has stronger bonding resistance than smooth steel tube, about 2-3 times than common mortar anchor bolt.