Research on Grouting Parameters of “Expansion-Grouting” Anchoring Technology for Soft Rock Roadway Floor Anchor Cables

Abstract

The “expansion–injection” anchoring technology of anchor cables in the bottom plate of soft rock roadways can not only give full play to the advantages of expansion anchoring to improve the anchoring effect of anchor cables in soft rock roadways, but also enhance the bearing capacity of the injected rock mass through grouting, thereby optimizing the stress distribution of the bottom plate and reducing the damage of the surrounding rock caused by tensile stress. Since the selection of grouting process parameters will directly affect the diffusion range and penetration effect of the grout, and the selection of grouting process parameters is often determined by experience and lacks scientific basis, this study uses numerical simulation to explore the influence of common grouting parameters such as grouting pressure, grouting time and the spacing of grouting anchor cables on the diffusion range of the grout. In order to provide a scientific basis for optimizing the design of roadway support. The numerical analysis results show that the grout diffusion radius increases nonlinearly with the increase of grouting pressure, while the expansion efficiency of the grout diffusion range gradually decreases and tends to be stable with the increase of grouting time. Meanwhile, a larger spacing of grouting anchor cables is not conducive to the formation of the grouting reinforcement area of the base plate. Finally, the reasonable parameter range was determined as the grouting pressure of 3-4 MPa, the grouting time of 8-10 minutes, and the anchor cable spacing of 2.5-3 m.