| Traditional fully mechanized coal mining faces have problems such as large numbers of people,low work efficiency,and roof damage caused by repeated supports,which severely restrict the development of safe,efficient and intelligent production systems.This paper uses a combination of rock physical mechanics experiment,theoretical analysis,numerical simulation and field measurement to explore the stability control of the surrounding rock in the advanced section of the 2901 working face of Juji Coal Mine.Through calculation and analysis of the stress concentration and distribution range of the surrounding rock in the leading section of the mining roadway,it provides a basis for the selection of the leading reinforcement support model of the mining roadway and the selection of the leading reinforcement support model for cutting the top and reducing the pressure and leaving the roadway along the gob.By exploring two types of mining The roof stress distribution rules and surrounding rock deformation characteristics of the advanced section of the roadway provide guidance for the stability control of the surrounding rock of the advanced section of the mining roadway;on this basis,it is proposed to replace the conventional advanced support with reinforced anchors to achieve improved support.At the same time of intensity,labor intensity is reduced,and repeated damage of roadway is reduced.Based on the above research,the main results of this article are as follows:(1)According to the layout conditions of the return air tunnel in the 2901 working face,a mechanical model of the surrounding rock of the inclined trapezoidal mining roadway was constructed,the expression of the plastic zone distribution of the surrounding rock was deduced,and the maximum plastic zone radius of the roadway roof was determined to be 5.31 m.Based on the suspension theory,the mechanical structure model of the anchor cable support of the roadway was established,the roof stability anchor cable support strength expression was obtained,and the roof anchor cable support strength of the advanced section of the mining roadway was determined to be 137.89 KPa,which requires reinforced support The intensity is 36.89 KPa.Numerical simulation comparatively analyzed the plastic zone,stress and surrounding rock deformation distribution characteristics of different reinforcement support schemes,and determined that the reinforcement anchor cable support scheme of the front section of the return air tunnel of the working face is: "4-2-2 along the direction of the roadway"-2-4" way to circulate arrangement.(2)According to the layout conditions of the transportation lane in the 2901 working face,the roof displacement structure model of the cut-top decompression and the uncut-top decompression and the remaining roadway along the goaf were constructed respectively.The research showed that the roof subsidence of the cut-top decompression along the gob was reduced.46.4%,the support strength decreased by 40.4%.The FLAC3 D software was used to compare and analyze the original roadway support and the conditions of different numbers and arrangement angles of reinforcing anchor cables,the stress distribution and surrounding rock deformation distribution characteristics of the roadway along the gob with the top-cutting pressure relief,and the reasonable cut-top pressure relief of the roadway retention along the gob was determined.The support plan is: a "4-3-3-3-4" circular arrangement along the direction of the roadway,and the anchor cable on the side close to the coal bank slopes outward by 20°.(3)Field measurements show that the leading supporting pressure range of the return airway is 30 m,and the leading supporting pressure range of the transportation lane is 40 m.The maximum displacements of the right and left sides of the return airway are 134 mm and 120 mm,respectively.The maximum displacements of the roof and bottom plates are 81 mm and 170 mm,respectively.The maximum deformation of the roadway beyond 30 m ahead of the working face does not exceed 60 mm.The surrounding rock deformation of the leading section of the return air tunnel is generally small,which effectively controls the surrounding rock deformation in the dynamic pressure zone of the mining roadway.When the transportation lane is 40 m ahead of the working face,the surrounding rock deformation of the roadway is severe;the range of 0-40 m lagging working face is affected by the supporting pressure of the mined area.The deformation of the roadway gradually slows down after the lagging working face is 40m;after the lagging working face 100 m,the surrounding rock deformation is severe.The deformation of the roadway tends to be gentle.In the end,the roof sinking amount of the reserved lane along the goaf is 576 mm,the right side approaching amount is 626 mm,and the bottom drum amount is 669 mm.The overall deformation of the surrounding rock of the remaining roadway is within the allowable range,the surrounding rock is complete and stable,and the supporting effect is good.There are 59 figures,9 tables and 75 references in this paper. |
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