Study On Supporting Technology Of The Compression End Anchorage And High Pre-tightening Force Anchor

To solve the problem that anchor pre-tightening force is hard to be applied, low bearing capacity, poor initial supporting effect, the article proposes a new type anchor suitable for tunnel surrounding rock support that called the compression end anchorage and pre-tightening anchor supporting method. With theoretical analysis,numerical simulation and model experiment, this paper analysis the supporting principle, structure form, construction technology, shear stress distribution of the compression end anchorage and pre-tightening anchor, obtaining the following main conclusions:1)The compression end anchorage and pre-tightening anchor is a new supporting technology that provide rapid and high pre-tightening force initial support and combined resin capsule’s rapid soildfication character with grout body’s compressive character;2)The bolt body of the compression end anchorage and pre-tightening anchor is unbound to the grout body, the pre-tightening force that can be applied is significantly improved; also the anchor just need to wait about 25 s gel time that can be applied the initial pre-tightening force to have good and rapid supporting effect on surrounding rock;3)Compared with the traditional tension-type grouting bolt, compression end anchorage and pre-tightening anchor have high bearing capacity,better supporting performance; and the two different type anchor have an opposite anchorage position on surrounding rock;4) The best borehole diameter size of compression end anchorage and pre-tightening anchor is 75 mm, in this borehole diameter, the anchor can not only provide high bearing capacity, but also ensure the economic benefits;5) The smaller the E_a/E_b,E_a/E_c is, the bigger the anchor shear stress distribution length, the smaller the shear stress peak, the bigger the anchor bearing capacity, the better the surrounding rock supporting effect.