覆岩主关键层对超前支承压力的影响规律研究

发布时间：2018-07-11 21:27

  本文选题：主关键层 + 支承压力　； 参考：《中国矿业大学》2015年硕士论文

【摘要】：超前支承压力分布对工作面巷道超前支护、煤与瓦斯突出与冲击地压等煤矿工程问题都将产生直接的影响,为了掌握工作面超前支承压力的分布规律,本文综合运用数值模拟、理论计算、数学分析等方法,研究了主关键层对工作面超前支承压力的影响特征,并得出了其影响程度的评价指标,建立力学模型分析了其影响机理,研究了主关键层对工作面超前支承压力的影响随其厚度与层位的变化规律,得出了主关键层对工作面超前支承压力产生影响的条件并建立了相应的预测模型,最后结合淮北海孜煤矿进行了应用,取得了以下成果:(1)通过UDEC模拟得出,主关键层影响下,支承压力峰值集中系数减小,超前影响范围增加,支承压力在峰值之后的衰减速度变慢。选择平均绝对离差作为主关键层影响程度的评价指标,定义该指标达到0.05为主关键层对支承压力有影响的标准。采宽小于临界采宽时,主关键层对超前支承压力无影响;随采宽增加,影响程度逐渐增加,主关键层初次破断前影响程度达到最大值;之后其影响程度随主关键层的周期性破断而波动。(2)借助弹性力学中的弹性地基梁与楔形体力学计算模型求解了主关键层传递至煤层的应力,研究得出主关键层影响支承压力的机理为:主关键层的抗弯刚度较大,采宽相同时支点处的下沉量小于软岩,而发生挠曲的范围大于软岩,导致主关键层对下方岩体的载荷传递至煤层后表现出上述特征。(3)通过数值模拟与理论计算研究了主关键层对支承压力的影响随其层位、厚度的变化规律:其他条件相同时,主关键层距煤层越远、厚度越大,超前支承压力峰值集中系数越小,超前影响范围越大;主关键层最大影响程度随其厚度增加而增加,随其与煤层距离增加而减小,当主关键层与煤层距离大于其临界层位后便不再对支承压力产生影响。(4)基于数值模拟的结果,采用线性回归的数学分析方法提出了主关键层对支承压力影响的预测模型,并应用到淮北海孜煤矿Ⅱ102采区,得出该覆岩条件下最大采动影响范围达到294.8m,Ⅱ1026机巷处于Ⅱ1024工作面回采后的应力集中区,解释了Ⅱ1026机巷发生动力灾害的原因。
[Abstract]:The advance support pressure distribution will have a direct effect on the coal mine engineering problems such as roadway support, coal and gas outburst and impact ground pressure. In order to master the distribution law of the working face leading support pressure, the numerical simulation is used comprehensively in this paper. By means of theoretical calculation and mathematical analysis, the influence characteristics of the main key layer on the leading bearing pressure of the working face are studied, and the evaluation index of its influence degree is obtained, and the influence mechanism is analyzed by establishing a mechanical model. The influence of the main key layer on the leading bearing pressure of the working face is studied. The influence conditions of the main key layer on the leading supporting pressure of the working face are obtained and the corresponding prediction model is established. Finally, combined with Huaibei Haizi coal mine, the following results have been achieved: (1) through UDEC simulation, under the influence of the main key layer, the peak concentration coefficient of the supporting pressure decreases, and the leading influence range increases. The attenuation rate of the supporting pressure after the peak value becomes slower. The average absolute deviation is chosen as the evaluation index of the influence degree of the main critical layer, and the index is defined to reach the standard of 0.05 for the influence of the main critical layer on the supporting pressure. When the mining width is smaller than the critical mining width, the main critical layer has no effect on the leading support pressure, and with the increase of the mining width, the influence degree increases gradually, and the influence degree of the main critical layer reaches the maximum before the first break. Then the influence degree fluctuates with the periodic breaking of the main critical layer. (2) the stress transferred from the main key layer to the coal seam is solved by means of elastic foundation beam and wedge mechanics calculation model. It is found that the mechanism of the main critical layer affecting the bearing pressure is that the flexural stiffness of the main critical layer is large, the settlement at the fulcrum is smaller than that of the soft rock when the mining width is the same, and the range of deflection is larger than that of the soft rock. As a result, the load of the main key layer on the rock mass below shows the above characteristics. (3) through numerical simulation and theoretical calculation, the influence of the main key layer on the bearing pressure varies with the layer and thickness: when the other conditions are the same, the influence of the main key layer on the bearing pressure is studied. The farther the main key layer is from the coal seam, the greater the thickness, the smaller the peak concentration coefficient of the leading supporting pressure, the larger the leading influence range, the greater the maximum influence degree of the main key layer increases with the increase of its thickness, and the smaller the distance between the main and the coal seam is. When the distance between the main critical layer and the coal seam is greater than its critical layer, it will no longer affect the bearing pressure. (4) based on the results of numerical simulation, a prediction model of the influence of the main critical layer on the supporting pressure is proposed by using the mathematical analysis method of linear regression. And applied to 鈪，

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