Grouting and subsidence reduction technology for separated layers of overlying strata at coal mines
In order to mine the No.11-3101 working face under the railway at Menkeqing Coal Mine and improve the recovery rate of coal resources,we applied the separation layer grouting technology to solve the ground depression,tested the rheological properties of different ratios of filling slurry through indoor experiments,determined the appropriate slurry ratio,and constructed a mechanical model of the evolution of separated layers in the overburden under mining.Accordingly,we proposed a prediction method for the dynamic development position and crevice width of separated layers.The research results showed that there were four separated layers from bottom to top of the working face,located at 45.42,228.38,337.19 m,and 363.99 m above the working face roof;the crevice width of separated layers from bottom to top was 2.62 m,1.49 m,1.39 m,and 1.33 m,respectively,and the width decreased with the increase of layer level;when the grouting pressure was 6.5 MPa and the grouting-mining ratio was greater than 45%,the surface inclined deformation value was less than 3 mm/m,and the field monitoring results showed that the maximum subsidence of railroad bed was only 58.72 mm,indicating that the grouting had a significant effect on subsidence reduction.
overlying strata under mining influencegrouting in separated layersfilling slurrysurface deformation
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