Research And Application Of Floor Heave Control Technology In Secondary Mining Roadway Of Yinxing No.1 Coal Mine

In view of the phenomenon of the bottom drum under the disturbance of secondary mining,this paper takes the return air lane of the 07 working face of Yinxing No.1 well as the engineering background.The paper studies the mechanism of the bottom drum by laboratory test,theoretical analysis and numerical simulation.Combined with the geological characteristics of the roadway,the paper puts forward the reinforcement control technology of the bottom drum of "the prestressed anchor cable at the top + grouting bolt of the floor",and carries out the engineering practice.The main results are as follows:(1)Through on-site sampling and laboratory test,the physical and mechanical parameters of coal and rock mass such as compressive strength,tensile strength and shear strength are measured.It is clear that the surrounding rock of roadway has the characteristics of hard roof and weak coal seam and floor;The deformation of surrounding rock is measured,and the deformation characteristics of surrounding rock are obtained,such as the maximum floor heave,the right side(coal pillar side)is larger than the left side(07 working face side),and the floor near the right side is larger than the left side.(2)This paper establishes the floor stress evolution and numerical calculation model in each stage of driving,primary mining and secondary mining of air return roadway in 07 working face,analyzes the floor stress distribution characteristics in different stages,illustrates the dynamic evolution process of stress and strain in two sides of roadway,and reveals that high stress is transferred to the floor through the left and right sides of roadway,The mechanism of floor heave caused by extrusion flow is that the floor rock is sliding and dislocated.(3)The applicability,advantages and disadvantages of different floor heave control methods are compared and analyzed.Based on the mechanism of extrusion flow floor heave and the production conditions of air return roadway in 07 working face,three floor heave control schemes with "floor(reinforcement)modification +wall reinforcement" as the main mode are proposed.FLAC3 D simulation software was used to simulate and analyze the floor heave control effect of the three reinforcement schemes.The results show that the support scheme 3(105 ° hollow grouting bolt with bottom angle of 1400 mm row distance + One ?17.8 × 5300 mm prestressed anchor cable with row spacing of 1600 mm on the left side of roadway +two ?17.8 × 5300 mm prestressed anchor cables with row spacing of 1500 × 1600 mm on the right side of roadway)has the best support effect.Under the influence of secondary mining,the maximum floor heave of the roadway is 105 mm.(4)According to the designed reinforcement and support scheme,the industrial test is carried out in the return air roadway of working face 07,and the construction technology and requirements of roadway support are put forward and implemented.The monitoring results of surrounding rock deformation show that the maximum amount of bottom drum at the measuring point is 210 mm,which shows that the bottom drum control method based on "floor(reinforcement)modification +reinforcement of the upper part" can solve the problem of the bottom drum with extrusion flow in the roadway.There are 57 figures,9 tables and 68 references in this paper.