Key parameters and stability analysis of roof cutting and roadway retaining in Jixian Coal Mine

Abstract

Aiming at the problem of cutting roof and retaining roadway on the right third working face of 16#, east second mining area of Jixian Coal Mine in Shuangyashan city, the mechanical model of surrounding rock of cutting roof and retaining roadway is established, and the theoretical calculation formula of key parameters such as cutting height and cutting angle is given; the influence of roof cutting parameters (roof cutting height and angle) on the stress distribution and deformation characteristics of the surrounding rock is further analyzed. The numerical simulation results show that the greater the roof cutting height is, the better the relief effect is; with the increase of the cutting angle, the side stress of solid coal shows an increasing trend, which also creates certain conditions for the caving of gangue. The similar simulation results show that when the coal seam is mined to a certain distance, the upper rock stratum in the goaf collapses at the same time, and the rock mass in the slit range and caving rock mass form a hinged joint, that is, the side filling of the roadway is basically completed, and the structure of “low cantilever beam + high hinged rock beam” is formed above the roadway. The engineering practice show that the cutting height is 8.0 m (2.39 m medium sandstone), the cutting angle is 10°, and the spacing of the drilling holes is 600 mm. When it is about 60 m away from the working face, the roof subsidence is 168 mm, the solid coal wall displacement is 212 mm, the deformation of the gangue wall is almost 0, and the bottom heave is 120 mm.

Keywords

• mining without coal pillar
• roof cutting and pressure relief
• gob-side entry retaining
• roof cutting height
• roof cutting angle