Reinforcement mechanism of self-drilling hollow anchors

Self drilling hollow anchors were first used in America coal mines in 1970s and began applicated in China in 1980s. Due to its fast construction speed and good anchoring effect, it has been widely used in deep foundation support projects, and gradually replacing the traditional steel anchor bar and seamless anchor bolt. Why self-drilling hollow anchor is so popular? The reason is its reinforcement mechanism.

The reinforcement mechanism is as follows: Self drilling anchor bolt is mainly composed of hollow anchor bar, drill bit, plate, nut and coupling. Hollow bar's surface has continuous wave thread with international standard, which can be directly connected with the output end of drill rig to complete drilling.

During drilling, hollow bar serves as a drilling rod and medium transmission channel, and it also acts as a stiffened body for geotechnical support after the completion of the project. When drilling into rock formations, compressed air or water can be injected. The air or water is used to flush out the rock fragments generated during the drilling process, and finally cement slurry is injected for anchoring. It can be grouted simultaneously when drilling into the soil layer. On the one hand, the cement slurry can drain the excess soil debris out of the hole. On the other hand, it can also consolidate the loose hole wall to prevent collapse and achieve better anchoring effect.

In a word, the integral anchoring system composed of hollow anchor bar, drill bit and coupling and connecting sleeve can be directly drilled after connecting with drill rig. And after drilling, the hollow bar can be grouted without pulling out. And after the slurry solidifies, self-drilling anchor bolt can act as stiffened body for supporting. The reinforcement mechanism of self-drilling hollow anchor is to integrate the functions of drilling, grouting and anchoring, which solves the problem of easy collapse in soft geology and realizes fast anchoring, safe and convenient efficient construction.