Abstract: As the mining depth increases, the floor heaves has become the main factor which influences the safety production and economic interest of the mine, and the pre-tensioned cable bolt with grouting is an effective way to deal with the floor heave. Because of the lack of professional and effective grouting sealing devices, the procedure of grouting with pre-tensioned cable bolt has become complicated, ineffective and unqualified. The sealing mechanism of the grouting hole with pre-tensioned cable bolt has been analyzed in this paper. The K-ε two-dimensional turbulence model has been adopted to conclude the flow field distribution principle of slurry under different sizes of sealing length and sealing annulus. It has analysed the flow velocity and pressure variation characteristics of slurry in the sealing annulus. Then the relatively reasonable sealing length and sealing annulus have been determined. Fluid theory has been used to calculate the slurry loss and to find out the optimum size of sealing length and sealing annulus, which has provided theoretical basis for the structure size design of the sealing device and the proportioning of sealing materials in the slurry pocket. Using the research result, it has developed a new sealing device for the grouting bolt hole with pre-tensioned cable.

Key words: floor cable, sealing mechanism, sealing length, size of sealing annulus, new-type sealing device