Collaborative application of directional blasting presplitting and flexible formwork concrete wall technologies in Chengzhuang Coal Mine

In order to improve the recovery rate of coal resources in general, Chengzhuang Coal Mine has carried out and implemented the technology of gob-side entry retaining in 5309 large height mining face. In view of the complex conditions such as 6 m thick coal seam and hard thick rock stratum in the roof, the application of directional blasting presplitting and flexible formwork concrete technology in the mining face of “thick coal seam and hard roof” is emphatically discussed by means of theoretical analysis and field test. The results show that the deformation of gob side entry retaining roadway develops rapidly within 10-90 m behind the working face; the wall pressure of gob-side entry retaining reaches the maximum within 50-100 m behind the working face; the cooperative application of blasting presplitting, roof cutting and pressure relief and flexible formwork concrete wall not only reduces the influence of periodic pressure on the roof of the roadway reserved along the goaf, but also enhances the bearing capacity of the roadway side, which obviously improves the overall stability and reliability of the roadway.