沿空回采巷道蝶叶型非对称底鼓机理

Mechanism of Butterfly-failure Asymmetric Floor Heave in Mining Roadway Along a Goaf

针对保德矿81306二号回风巷底板产生非对称破坏,造成巷道非对称大变形底鼓问题,引入蝶形塑性区理论,结合理论分析和数值模拟分析研究了沿空回采巷道蝶叶型非对称底鼓机理。研究表明了沿空回采巷道受采动应力影响,围压比成倍增加,产生蝶形破坏,最大主应力方向向采空区一侧倾斜,导致产生的蝶形塑性区蝶叶旋转到巷道底板一侧,底板蝶叶内岩石遭到严重破坏,从而产生剧烈的非对称性底鼓,这种底鼓定义为蝶叶型非对称底鼓。针对保德矿沿空回采巷道蝶叶型非对称底鼓,结合数值模拟方法,提出通过适当增加煤柱宽度的控制思路来确定沿空巷道煤柱尺寸,从而调整蝶形塑性区蝶叶旋转角度,降低回采巷道围压比。

Aiming at the problem of asymmetric large deformation floor heave in the 81306 No.2 return air roadway of Baode Coal Mine, and this paper introduces the butterfly-failure theory, combined with theoretical analysis and numerical simulation analysis,and studies on mechanism of butterfly-failure asymmetric floor heave in roadway along a goaf. The results show that the confining pressure ratio increases exponentially, butterfly-failure emerges in mining roadway along the goaf under the influence of mining disturbance, and the maximum principal stress is tilted to the side of the goaf, which makes butterfly blade of butterfly-shaped plastic zone rotate to the side of the roadway floor, and the rock in floor butterfly blade is badly damaged to result in a violent unsymmetrical floor heave, the floor heave is defined as the butterfly-failure asymmetric floor heave. According to the butterfly-failure asymmetric floor heave in Baode Mine, combined with numerical simulation method, it is suggested that the size of pillar along the goaf should be determined by controlling the width of coal pillar appropriately, so as to adjust the rotation angle of butterfly blade and reduce the confining pressure ratio of roadway.