超长孤岛综放工作面支承压力分布规律研究

为对超长孤岛综放工作面围岩稳定性和顶煤冒放性进行控制,采用FLAC3D有限元软件对比分析了超长孤岛工作面的支承压力分布特征。研究老顶上覆岩层应力场的变化规律,分析初采期间和正常推进期间工作面超前支承压力分布规律。老顶岩层内工作面超前支承压力存在两个峰值区域,工作面后方支承压力沿面长方向的中间存在一个峰值区域,两者之间为低支承压力区域。顶煤层位支承压力峰值大于煤层的机采层位,但支承压力的影响范围小于机采层位,且顶煤的极限平衡区宽度较机采层大。工作面正常推进期间较初采期间的支承压力极限平衡区宽度增大,孤岛工作面加长后支承压力峰值系数在初采期间增加,而在正常推进期间降低。超长孤岛工作面减小孤岛工作面侧向支承压力的叠加影响。

RESEARCH ON ABUTMENT PRESSURE DISTRIBUTION LAW OF OVERLENGTH ISOLATED FULLY-MECHANIZED TOP COAL CAVING FACE

In order to control the stability of surrounding rock mass and the capability of top-coal for overlength isolated fully-mechanized top coal caving face,the distribution characters of abutment pressure for the working face are analyzed contrastingly with finite element software.The stress field variation law for overlying main roof is studied.The front abutment pressure distribution law of FLAC3D working face for coal seam during initial and normal mining stages are analyzed.Two peak value areas exist of working face front abutment pressure,and one peak value area of rear abutment pressure exists in the middle section along working face.A low abutment pressure area exists among the two front abutment pressure peak value areas and gob peak value area in the main roof.The peak value area of gob abutment pressure will evolve into three peak value areas in the location away from wall.The abutment pressure peak value of top coal is bigger than that of the coal mined with cutter,but the influencing scope of abutment pressure of top coal is less than that of the coal mined with cutter,and the limit equilibrium section width of top coal is also bigger than that of the coal mined with cutter.The limit equilibrium section width of abutment pressure at beginning of mining is bigger than that during normal mining.When the width of isolated working face is lengthened,the peak value coefficient of abutment pressure increases at initial mining period,but reduces during the course of normal mining.Overlength isolated working face reduces the superposed influence of two sides abutment pressure on isolated working face.