Research On Surrounding Rock Control Technology Of Tailentry In 41213 Working Face Of Dafosi Coal Mine

Aiming at the technical problem of controlling the surrounding rock of tailentry in41213 working face of Dafosi Coal Mine,the deformation and instability characteristics of surrounding rock are analyzed through field investigation,experiment of physical and mechanical parameters of coal and rock and combined with geological conditions.On this basis,theoretical analysis and numerical simulation are used to analyze the mining effect of adjacent working face,and a technical scheme of strengthening surrounding rock with tailentry in 41213 working face is put forward.The results of this paper are verified by field industrial test.The main conclusions are as follows:(1)The surrounding rock of the 41213 working face in Dafosi Coal Mine is strongly moved inwards,the roof subsidence and the bottom heave are serious after the tailgate is affected by mining of the adjacent working face.The test results of roadway surrounding rock cracks show that the surrounding rock is fractured,the joint cracks are developed and there are more cinders in the hole after drilling,which seriously affect the anchoring effect of anchor cable.Structural stress,mining influence,unreasonable supporting method and supporting parameters are the main reasons that cause roadway instability and failure.(2)The original support can maintain the normal use of the roadway without the influence of the mining of the adjacent working face,but when the roadway is affected by the mining,the roadway two sides will be destroyed first,and then lead to the whole roadway section deformation and instability.The results show that the large plastic deformation of roadway wall has an important influence on the stability of roadway roof.(3)Based on the mechanical characteristics and deformation characteristics of the surrounding rock of the tailentry in 41213 working face,the reinforcing technology of high-strength and stable type anchor cable is proposed.That is,outside the area affected by the advance mining of adjacent working face,high strength prestressed anchor cable is used to reinforce the two sides and roof of roadway,and the extremely uneven deformation and destruction of surrounding rock mass of roadway is controlled by the coordinated support of anchor cable and bolt.The bearing capacity of the original boltmesh support is greatly improved by the secondary pretension or tension of the existing bolt-cable.(4)In order to solve the problem of poor anchoring performance of cable in broken surrounding rock,the special-shaped cable is proposed.In order to improve the anchoring reliability of anchor in broken surrounding rock,an umbrella reed device is installed at the end of anchor.(5)The field industrial test results show that the deformation and failure degree of the surrounding rock of the reinforced roadway decreases obviously and the stability of surrounding rock increases remarkably,which ensures the normal use of the roadway during the mining of this working face.There are 79 pictures,12 tables,and 100 references.