| With the gradual depletion of shallow coal resources,coal mining gradually turns to deep,weak surrounding rock roadway is prone to roof breakage and section contraction and other problems,which brings a lot of trouble for efficient production and working environment.Based on the engineering geological characteristics of No.2 coal seam South No.1 mining area in Liuxin coal mine,this paper analyzes the main control factors affecting the stability of surrounding rock of mining roadway by using the research methods of theoretical analysis,numerical simulation and industrial test,and obtains the surrounding rock control technology based on the geological characteristics of the mine.The corresponding results can provide scientific basis and theoretical support for the stability control of mining roadway.The research contents of this paper are as follows:The research contents of this paper are as follows(1)By analyzing the engineering geological characteristics of No.2 Coal Seam in South No.1 mining area,it is obtained that the soft rock in this area mainly exists in the roof and floor of No.2 Coal Seam in the form of gray black shale and mudstone;by co MParing the mechanical parameters of rock strata and engineering rock mass classification standards in South No.1 mining area,it is concluded that the roof and floor of No.2 coal seam belongs to typical engineering soft rock.(2)Through the method of theoretical analysis,this paper analyzes the deformation and failure mechanism of soft rock roadway in South No.1 mining area,and concludes that the degree of plastic deformation and failure of roadway is related to the mechanical properties of surrounding rock and the radius of roadway section.Based on the same conditions of buried depth,engineering geological environment and support mode,through the deformation data of three typical roadways in the first mining area of siminan,it is determined that the lithologic strength is the main controlling factor affecting the deformation and failure of surrounding rock.(3)The deformation characteristics of soft rock roadway without support in No.1 mining area of South China are analyzed by numerical simulation.It is concluded that the roof rock of soft rock roadway is prone to tensile and shear failure,and the failure depth at the shoulder corner of arched roadway is relatively large.It is determined that the bolt mesh cable is used to enhance the support strength,fully mobilize the bearing capacity of surrounding rock,and the bolt mesh shotcreting +U-shaped steel is used to improve the coordinated deformation capacity of surrounding rock The idea of surface support to prevent weathering.(4)Numerical simulation is used to analyze the stress distribution and deformation of roadway with different anchor cable density,length and bolt mesh spray + U-steel support.It is concluded that the support scheme with anchor cable length of 8.3m and anchor length of 1.0m is determined when the anchor mesh spray+ U-steel is used as the main support component,and the type and thickness of U-steel is determined when the anchor mesh spray + U-steel is used as the main support component The distances are 36 U and 0.8m respectively.Considering the economic cost and construction method,the industrial test of anchor mesh cable support method is determined(5)The results show that the average deformation of roof and floor is 56 mm and that of two sides is 30 mm during driving,and the variation range of bolt(cable)stress is very small;the displacement of roof and floor is 500 mm during mining,The shrinkage of the two sides is 257 mm.The results show that by increasing the number and length of the top anchor cable,selecting the anchor with higher strength and longer anchorage length,laying metal mesh and other surface protection materials can achieve good surrounding rock control effect.There are 46 pictures,17 tables and 72 references. |
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