Research on the application of new inorganic grouting material to the reinforcement technology of broken coal body in working face

Based on the soft and broken coal body and roof and floor of large mining height in Zhaogu No.2 Coal Mine, different degrees of roof leakage and coal wall spalling occur in the production process, and the current treatment method for the mine is chemical grouting, the grouting cost is high and the effect is not ideal. In order to solve the problem of roof and floor and coal wall spalling, a new type of inorganic grouting material is prepared and used in mine industrial test. The fluidity of the new material is tested. The results show that when the water-cement ratio of A slurry is 0.4-0.5, the fluidity is good, which is in line with the field practical application. The stability test show that the water-cement ratio of A slurry is 0.4, and the setting time show that the water-cement ratio is 0.4, and the strength of the solidified body decreases with the increase of B slurry. When the volume ratio of A slurry and B slurry reaches 5∶1 and above, the compressive strength of the inorganic double liquid slurry stone body can reach more than 7.6 MPa. When the mass ratio of A slurry to B slurry is 40∶1, the compressive strength and flexural strength are the highest. The grouting test is carried out in two stages, and the boreholes are arranged reasonably. Through the industrial test, the slurry diffusion and filling cracks exposed by the mining are observed on the spot. The results show that the diffusion radius of the new inorganic double slurry could reach about 10 m, and the crack filling is relatively complete and dense, which achieved good results and met the normal mining of the working face.