Abstract: In response to the effects of roadway excavation disturbance and grouting pressure decay on the law of slurry penetration and diffusion, an unsteady seepage diffusion basic equation of slurry within surrounding rocks under coupling effect of disturbance stress and grouting pressure has been derived by using seepage flow mechanics theory based on the quasi continuum hypothesis. A numerical calculation model of slurry penetration and diffusion within surrounding rocks during bolt-grouting process has been established by using COMSOL software. The effects of grouting time, grouting pressure and grouting bolt interval on the slurry penetration and diffusion have been systematically studied. The results show that prolonging grouting time can slow down the attenuation of the hydraulic slurry head during the diffusion process, but increase the diffusion radius of the slurry within surrounding rocks at the end. The grouting slurry will form a whole grouting reinforced circle in surrounding rocks when the ratio of grouting bolt interval to slurry diffusion radius is less than or equal to 1.41. Finally, these results have been applied to the design of roadway bolt-grouting supports in the Yuanyi coal of the Huaibei mine. The field monitoring proves that the bolt-grouting method effectively controls the deformation and damage of roadway surrounding rock.

Key words: disturbance stress, whole section bolt-grouting, penetration diffusion, bolt-grouting parameters, grouting reinforced circle