Mechanism of Roof Cutting and Pressure Relief for Double Roadway Arrangement in Thick Coal Seam

Abstract

[Purposes] This research is conducted to exploret the roof movement law of double roadway arrangement in thick coal seam and the abutment pressure distribution mechanism of surrounding rock. [Methods] The roof cuttings of single roadway in belt channeling and return air channeling in Gucheng N1302 face were taken as the engineering research objects to achieve effective pressure relief in double roadway. Theoretical analysis, field tests, and numerical simulation were used to investigate the mechanism of roof cutting and pressure relief on double roadway arrangements. [Findings] The results show that, according to theoretical calculation, the range of the internal stress field increases obviously after roof cutting, which can effectively reduce the stress of the belt along the groove. Field tests show that the deformation of the surrounding rock is significantly reduced when the top cutting height is 20 m, but the key layer of the upper level turns ahead of time, increasing the floor heave during the service of the return air channeling channel. The numerical simulation results show that the vertical stress of the coal wall is not affected by increasing the cutting height when the upper key layer is not cut off. While when the upper key layer is cut off, the vertical stress of the coal wall in the return air channeling channel decreases obviously. When the cutting height of the top is fixed, changing the width of the coal pillar between lanes can control the stress of the return air channeling.

Keywords

• double roadway pressure relief
• internal and external stress field
• overburden structure
• rock pressure development