Analysis on Grouting Reinforcement Results in Secondary Support of Soft Rock Roadway in Kilometre Deep Mine

According to the later grouting results of the mine roadway could not be ensured,based on the analysis on influence factors of the grouting results,an intrinsic safe YTJ20 borehole speculum method with a television image dye agent tracing liquid was applied to inspect the later grouting results of the kilometre deep mine soft roadway under the conditions of bolt and grouting support in Zhuji Mine.The results showed that the effective reinforcement scope of the later grouting mine roadway was 0~2.6 m.Within and out of the effective reinforcement scope,there were still broken zones in the surrounding rocks.In some of the large cracks and bed separations,there was no grouting trace found,which was caused by the shallow grouting boreholes of the mine roadway,over long space between the grouting borehole rows,grouting operation too later after the mine roadway headed and other factors.Therefore the grouting parameters of the mine roadway was optimized.The space between the grouting borehole rows was adjusted to 1.5 m×2.1 m.The grouting pressure would not be over 1.5 MPa.The delay time of the grouting operation would be controlled at 10~20 days after the mine roadway headed.The depth of the grouting borehole was set at 3.0 m.The space of the borehole row was set at 1.5 m×2.1 m.The grouting pressure should not be less than 2.0 MPa.The layout of the deep and shallow boreholes for the grouting boreholes should be an alternate layout.The deep borehole grouting should be operated about 30 days delay after the shallow borehole grouting operation.