Self Drilling Bolt’s Grouting Reinforcement in Loose Surrounding Rock of Tunnel
In loose stratum, surrounding rocks would probably appear sloughing and roof falling.
Grouting reinforcement refers that self drilling bolt is inserted into stratum along contour line of tunnel excavation and has certain extrapolation angle with hole axle. Self drilling bolt has dual functions, one is lead pipe shed function, the other is grouting pipe function.
Grouting reinforcement makes slurry permeate and diffuse in stratum hole or cracks through self drilling anchor bolt by virtue of grouting pump’s pressure to improve soil’s physical properties, enhance self-stable ability of excavation face and then reach to the purpose of restraining deformation of stratum.
The purpose of adopting grouting method to carry out pre-reinforcement is to form sealing ring with certain strength and thickness around contour line of tunnel excavation, then have function of load-bearing arch, with bearing gravity of upper stratum and making surrounding rock, support system in status of pressure-avoiding. The pressure mainly refers to deformation pressure from arch of tunnel, so the upper load will be decreased largely.
Through grouting method to reinforce surrounding rocks, stratum above arch crown would be reinforced and formed consolidated body. The entire stability will then be increased, temporary support in pipe shed will be strengthened and finally ideal excavation condition will be reached.