Self drilling anchor system’s inclination should be 15°~25° horizontal downward, no large than 45°. With increase of inclination, horizontal component of self drilling anchor system decreases. Too large inclination will reduce anchoring effect and increase vertical component on supporting structure, which will also cause settlement of retaining structure and surrounding foundation. To use self drilling anchor system’s pulling resistance effectively, self drilling anchor system should parallel with direction of side pressure effect.
Except meeting mechanical supporting condition, specific install direction of self drilling anchor system has a connection with location of anchoring stratum, retaining structure and construction condition. Inclination of self drilling anchor system should avoid the range of -10°~+10° with horizontal plane, because after grouting, slurry’s sediment and bleeding phenomenon will influence self drilling anchor system’s carrying capacity.
Self drilling anchor system’s carrying capacity is relative to limit friction resistance of soil body. Generally, soil texture at super stratum is poor than sub stratum, at the same anchorage length, the smaller inclination, the shorter anchorage body in good soil texture.
So, before formal construction, fundamental test of self drilling anchor system should be done to get relation between inclination and length and then provide design research decision.