沿空巷道切顶围岩变形控制机理及工程应用

为减少薄-中厚煤层开采工作面区段煤柱损失，提出了切顶法沿空成巷无煤柱开采技术，即在上区段回采工作面运输巷内，采用张拉聚能爆破在运输巷顶板与采场侧向顶板间形成一条切缝结构面，该结构面可阻滞采场侧向顶板移动压力向沿空巷道围岩的传递，并促使侧向顶板沿切缝切落，切落矸石则隔断采空区而形成运输平巷采空区侧巷帮，矸石碎涨后充填冒落空间支撑上位岩层继续移动，从而实现沿空巷道稳定。沿空巷道切顶力学模型的理论与数值分析结果显示，巷旁爆破切缝将可传递采场岩层移动变形压力的岩梁结构改变为沿切缝切落的短臂岩梁结构，大大降低了沿空巷道受采场侧向岩层移动变形压力的作用，减小了沿空巷道围岩压力及变形量。基于该原理提出的巷内加强支护、巷旁密集支护、巷道顶板切缝等主被动联合切顶技术，在各种不同条件下薄煤层、中厚煤层切顶成巷工程实践中均取得了良好效果，实践表明，该方法可有效降低采场岩层移动对沿空巷道产生的压力，减小沿空巷道围岩变形。

Study on deformation control of gob-side entry retaining with roof cutting and engineering application

To reduce the coal pillar’s loss at thin and medium coal seam,a new technique,entry roof cutting,for gob-side entry retaining without coal pillar has been put forward.That is to generate a structural plane of cutting seam by cumulative blasting between the roof of entry and the side roof of mined area in last working face,the structural plane may weaken the transfer of the mining face’s side roof movement to the surrounding rock and cut the roof along the cutting seam.The fallen waste rock separates the goaf and forms a gob,in addition,it fills the falling space to support the rock stratum above,finally,the gob-side entry retaining achieve its stability.The theory and numerical analysis of the mechanical model suggest that the cutting seam could change the rock beam structure,which could transfer the pressure of deformation of rock stratum,to the short cantilever rock beam structure which has low load and doesn’t transfer the pressure of deformation,thus could reduce the surrounding rock’s pressure and deformation of gob-side entry retaining.According to that principle,the technique has been put forward to combine reinforcing support in entry,supporting densely in the side of entry and the cutting seam of entry roof.The study shows a favorable effect in the project of roof cutting to form an entry within thin and medium coal seam in different conditions.The method could reduce the pressure from the move of rock stratum in mining and the deformation of surrounding rock effectively.