The Application For The Reinforcing Technology Of Surface Pre-grouting In The Construction Of Tunnel's Shallow And Fragmentized Area

The security of tunnel's excavation is always an important and difficult problem which tunnel constructor has to face, meanwhile, it is the condition of the rock what determinates definitively the security of tunnel's excavation. In a rock tunnel, the surrounding rocks around the orifice get characters below: a long range of shallow cover, fragmentation and weathering, bad stability. In order to protect the nature and keep the configuration of the surface and the stability of slopes, it is extremely important to do some pre-support.Relying on the Alatan tunnel in Lu-Huo highway, the paper carried out the study that how the grouting pre-support technology applies in the shallow cover surface of the tunnel orifice. The paper analyses detailedly the reinforcing principle of grouting pre-support technology in the tunnel's shallow cover, and, combining the geological condition of the tunnel and the field test of surface grouting, the paper confirm the logical material and ratio for grouting. According to the analyzing for the field test of pervasion radius, the author put forward the logical space between each grouting hole, the pressure and order of grouting, furthermore, aiming at some exceptional conditions, the author also put forward concerned pretreatment measure.By contrasting the monitoring and measuring result between grouting and not, the paper indicates that the grouting plan is logical, the reinforcing effect of grouting is evident, and finally, we achieve our goal of reinforce. The study is instructional and exemplary to the work of surface pre-grouting...