Research on Surrounding Rock Control Technology of Supporting-unloading Coordination of Gob-side Entry Retaining with Hard Roof
Aiming at the problem of large deformation of roadway surrounding rock caused by roof cutting and pressure relief and unreasonable support parameters in gob-side entry retaining with hard roof,taking the transportation roadway of a mine as the engineering background,the deformation characteristics of gob-side entry retaining in this mine were monitored and analyzed on site.The parameters of roof cutting and pressure relief were optimized by numerical simulation,and the control technology of supporting-unloading coordination surrounding rock in gob-side entry retaining with hard roof was studied.The re-sults show that the deformation of hard roof along goaf tunnel is characterized by four stages:advance and rapid deformation,lag and rapid deformation,slow deformation and gradual stability.The deformation of roof and floor and two sides of roadway is se-rious,the deformation period is long,and the lag working face distance reaches 230 m when the deformation of surrounding rock is stable.The existing support method and roof cutting and pressure relief parameters cannot effectively control goaf tunnel de-formation.The optimum cutting height and angle are 7 m and 15° respectively by optimizing the cutting pressure relief parame-ters.Based on this,the control technology of mutual coordination of large deformation anchor cable+single point column rein-forcement support is proposed while cutting roof and relieving pressure in gob-side entry with hard roof.Through the field test,the deformation of the roof and the deformation of the two sides of the roadway along the gob are reduced by 52.3%and 55.1%,and the deformation control effect of surrounding rock is remarkable.
hard roofgob-side entry retainingtop cutting and pressure reliefsupporting-unloading coordination
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