Differentiated Heaving Floor Three-dimensional Control Technology for Retaining Roadway Along Goaf Based on Distributed Monitoring

In view of the serious heaving floor problem caused by the existing problems of interlayer water softening of floor muddy sandstone and carbonaceous shale and stress asymmetric distribution in the section of retaining roadway along goaf of the deep coal mining working face in Taitou Coal and Coking Coal Mine, a method combining distributed fiber optic monitoring and three-dimensional numerical simulation is adopted. Based on the theory of surrounding rock stress field reconstruction, a heaving floor three-dimensional control technology for deep retaining roadway along goaf with anchor injection is proposed innovatively: the support strength of the coal pillar side reaches 1.7 times that of the solid coal side by laying out differentiated anchor rods with a diameter of Φ22/Φ20 mm; The P·O42.5 cement-silicon powder graded grouting system is adopted, combined with the 3.5 m deep hole and 2.1 m shallow hole staggered grouting process, a three-dimensional reinforcement network combining depth and shallowness is formed. The engineering application shows that this technology reduces the heaving floor amount from 312 mm to 89 mm, reduces the cross-sectional shrinkage rate to 8.3%, and improves the cohesion to 1.7 MPa, which successfully constructs a continuous strengthening bearing structure and effectively solves the difficult problem of asymmetric heaving floor in deep retaining roadway along goaf.