浅埋硬煤巷道煤体破坏特征与控制机理

Failure characteristics and control mechanism of shallow buried hard coal roadway

高覆岩应力影响下,硬煤巷道两帮煤体块落现象严重,为提高该类巷道安全稳定,选取榆北地区典型硬煤巷道为背景,结合现场实测、理论分析及数值计算综合手段对巷道煤体破坏特征及控制机理进行分析。结果表明:硬煤巷道两帮煤体内部环向裂隙发育,裂隙间隔在0.5~1.0 m左右,越靠近巷道,煤体裂隙发育程度越高;覆岩应力影响下,煤体板裂结构变形(0.017m)超2倍于材料变形(0.0077 m),巷道煤帮变形以结构变形为主;锚杆预应力越大,对于板裂煤体的控制能力越强。现场实测表明,提高两帮支护强度和预紧力后,帮部煤体变形减少了90%以上。

Under the influence of high overburden stress,the block falling phenomenon of two sides of hard coal roadway is serious.In order to improve the safety and stability of the roadway,typical hard coal roadway in Yubei area is selected as the background.Combined with field measurement,theoretical analysis and numerical calculation,the failure characteristics and control mechanism of roadway coal are analyzed.Results show that the inner circumferential fractures are developed in the two sides of hard coal roadway,and the fracture spacing is about 0.5-1.0 m.The closer the roadway is,the higher the degree of fracture development is.Under the influence of overburden stress,the deformation of the coal plate fracture structure(0.017 m)is more than twice that of the material(0.0077 m),and the deformation of the coal seam in the roadway is mainly structural deformation.The greater the prestress of the bolt is,the stronger the control ability of the cracked coal is.The field measurement shows that the deformation of coal body in the two sides is reduced by more than 90%after increasing the support strength and preload.