Geophysical criterion of pre-outburst coal outsqueezing from the face space into the working

The initial process of coal and gas sudden outburst is studied in the article when under the influence of rock and gas pressure the part of a coal seam layer(a coal section)is squeezed out from the mouth of the future outburst cavity in a jump-like manner into the working.Geo-mechanical criterion for a part of a coal seam layer outsqueezing in the form of the relation of active(squeezing out)and passive(preventing the outsqueezing)forces is defined in the article.Based on it,the geophysical criterion is defined by expressing basic physical parameters through geo-physical ones:the current stress is defined by spectral-acoustic method through the ratio of high frequency and low-frequency components of an acoustic signal,which is generated into a face working space by the mining equipment operating in the face;in-situ gas pressure is defined by gas analytical method by the concentration of methane in the atmosphere of the working;the strength of the most broken coal layer is defined by a strength measuring device(a device for measuring the depth of a steal cone punched into the coal by a spring mechanism).This paper studies the influence of acoustic,strength and filtrating and collecting properties of a face working space on the limit value of an obtained geophysical criterion of pre-outburst squeezing of a coal‘‘plug”out of the mouth of the future outburst cavity into the working.

不同屈服准则下回采巷道区段煤柱的合理宽度

以某矿为背景,对该矿6-6~#煤层开采中S_1段与S_2段区段煤柱合理宽度的问题进行了研究,基于摩尔库伦准则、SMP准则对区段煤柱的合理宽度进行计算,并采用FLAC^(3D)数值模拟的方法对6-6~#煤层S_1段采空后不同距离下S_2煤体中应力分布特征,及不同宽度的区段煤柱(6、8、10、12、14、16、18 m)下煤柱中的垂直应力、水平应力、煤柱中非塑性破坏宽度、以及S_2段巷道中围岩的位移情况进行分析;通过研究,最终确定该矿6-6~#煤层区段煤柱的合理宽度应为11~12m;通过将摩尔库伦准则、SMP准则计算所得煤柱宽度与模拟结果进行对比,发现模拟结果与SMP准则所得结果更接近。

基于SMP准则的综采工作面区段煤柱留设研究

针对综采工作面采出率低、煤炭资源浪费严重的问题,以马兰矿12505综采工作面为研究对象,基于SMP准则,对区段煤柱留设宽度进行了计算,确定煤柱留设宽度为20 m。通过对12505工作面轨道顺槽围岩变形情况进行观测,证明了区段煤柱留设方案的合理性。