Movement of overlying rock and deformation law of surface well under multiple mining with large dip angle

Abstract

Surface wells are prone to deformation and even instability under the mining action caused by coal seam mining. This is also a key issue that restricts the application of gas drainage technology in surface wells in mining pressure relief areas. Based on the mining of high-incline coal seam group in Xinjiang 1930 Coal Mine, this paper carried out similar simulation experiments of surface well deformation under high-incline coal seam group mining, by monitoring overlying rock movement, coal seamstress changes, and the axial and circumferential directions of different positions of surface well pipelines. Deformation reveals the law of deformation of surface wells under the mining of large-dip coal seams. Research shows that: first, surface wells are in a state of sheer, compression, and tension during the mining process. Most of the time, the shear deformation in the axial direction is greater than the tensile deformation in the axial direction, that is, the shearing action on the surface well is dominant. At the same time, during the mining process, the shear deformation in the circumferential direction and the axial expansion and contraction deformation of the surface well is negative to a certain extent. The correlation, to a certain extent, shows that the shearing and tensioning, and compressing effects of surface wells are mutually restrictive; secondly, the axial deformation of surface wells shows an increasing trend as a whole, but the phenomenon of tension and shrinkage alternates in the process, and there is a big difference in the constant increase in the repeated mining of the near-level coal seam, and the changing trend of the circumferential shear deformation is similar to that of the near-level coal seam. The direction of displacement is always the inclination direction of the coal seam; the final study also found that the surface well defamation law in the upper part of the main key layer showed an overall “increase-decrease” alternating three times, and “increase-decrease” in the main key layer and lower part. Repeat four times alternately. The research results can provide certain theoretical support for the engineering application of surface wells in high-dip multiple mining areas.

Keywords

• large dip seam
• multiple mining
• overburden
• movement surface well
• shaft deformation