Research on the application of pre-grouting reinforcement technology in roadway fracture zone

In order to prevent water inrush and water and sand collapse accidents caused by FD5 fault in a horizontal south wing transportation roadway and auxiliary transportation roadway, the geological conditions of the top and bottom aquifer of the primary coal seam in the mine were studied, the water inrush mechanism was analyzed, and the treatment method of "vertical drilling pre-grouting + continuous drainage water curtain" was proposed. Three vertical rows of boreholes are arranged through the fault plane of 5 coal, 8 coal and 15 coal respectively, and the aquifer within the range of 90m from the top of the aquifer of Zhiluo Formation to the bottom plate of coal 15 is injected by sectional grouting. Each row of boreholes is designed to reserve inspection holes, and a multi-purpose hole is achieved. The grouting results show that the grouting amount of a single hole is significantly affected by the grouting sequence, and the grouting amount of the boreholes constructed first is large. The pumping test of the inspection hole shows that the hydraulic connection between the holes decreases obviously after grouting. The cement filling was evident in the coring of the crack section and the grouting effect was verified. The grouting parameters were designed with reference to the experience of karst water curtain in eastern China, and the final pressure and final volume were not less than 3.47MPa and less than 60L/min respectively. The grouting effect was good.