错层位巷道布置工作面端头顶煤冒放性研究

Research on Top Coal Caving Property at Working Face End of Stagger Arrangement Roadway Layout

以镇城底矿地质情况为背景,通过对端头顶煤在传统放顶煤开采巷道布置和错层位巷道布置条件下受力规律的分析,认为在错层位巷道布置条件下,接续工作面上端头顶煤处于支承压力峰值区,且由于端头顶煤与上区段采空区相连,产生了一个自由面,有利于端头顶煤破碎;结合莫尔-库仑强度准则,自由面的产生使端头顶煤的最小主应力σ3变为0,处于应力峰值区使得最大主应力σ1的值升高,改变了端头顶煤的三向应力状态,加速了煤体破坏;运用数值模拟对该矿8#煤层分析,模拟结果与理论分析一致,因此认为错层位技术有利于工作面端部顶煤冒落。

Based on geological conditions in Zhenchengdi Mine,through the analysis of stress laws for end top- coal under the conditions of traditional roadway layout and the roadway layout of stagger arrangement,it is thought that end top- coal in the working face is in the abutment pressure peak value area under the condition of the roadway layout of stagger arrangement. At the same time,a free surface is created because the end top- coal and the prior sector goaf are linked together,which is conducive to the damage of the end head coal; combined with Mohr- coulomb strength criterion,the minimum principal stress in the end top- coal drops to 0 owing to the free surface and the maximum principal stress increases in the area of the peak stress,which changs the stress state of three- way in the end top- coal and accelerate the damage of coal; through the analysis by FLAC3 Dnumerical simulation on 8coal seam in Zhenchengdi Mine,it is thought that the simulation results are consistent with the theory. As a consequence,the conclusion that it is favorable for the end top- coal of working face to cave in technical conditions of the roadway layout of stagger arrangement is obtained.