本文選題：主關鍵層 + 支承壓力　； 參考：《中國礦業(yè)大學》2015年碩士論文

【摘要】：超前支承壓力分布對工作面巷道超前支護、煤與瓦斯突出與沖擊地壓等煤礦工程問題都將產(chǎn)生直接的影響,為了掌握工作面超前支承壓力的分布規(guī)律,本文綜合運用數(shù)值模擬、理論計算、數(shù)學分析等方法,研究了主關鍵層對工作面超前支承壓力的影響特征,并得出了其影響程度的評價指標,建立力學模型分析了其影響機理,研究了主關鍵層對工作面超前支承壓力的影響隨其厚度與層位的變化規(guī)律,得出了主關鍵層對工作面超前支承壓力產(chǎn)生影響的條件并建立了相應的預測模型,最后結合淮北海孜煤礦進行了應用,取得了以下成果:(1)通過UDEC模擬得出,主關鍵層影響下,支承壓力峰值集中系數(shù)減小,超前影響范圍增加,支承壓力在峰值之后的衰減速度變慢。選擇平均絕對離差作為主關鍵層影響程度的評價指標,定義該指標達到0.05為主關鍵層對支承壓力有影響的標準。采寬小于臨界采寬時,主關鍵層對超前支承壓力無影響;隨采寬增加,影響程度逐漸增加,主關鍵層初次破斷前影響程度達到最大值;之后其影響程度隨主關鍵層的周期性破斷而波動。(2)借助彈性力學中的彈性地基梁與楔形體力學計算模型求解了主關鍵層傳遞至煤層的應力,研究得出主關鍵層影響支承壓力的機理為:主關鍵層的抗彎剛度較大,采寬相同時支點處的下沉量小于軟巖,而發(fā)生撓曲的范圍大于軟巖,導致主關鍵層對下方巖體的載荷傳遞至煤層后表現(xiàn)出上述特征。(3)通過數(shù)值模擬與理論計算研究了主關鍵層對支承壓力的影響隨其層位、厚度的變化規(guī)律:其他條件相同時,主關鍵層距煤層越遠、厚度越大,超前支承壓力峰值集中系數(shù)越小,超前影響范圍越大;主關鍵層最大影響程度隨其厚度增加而增加,隨其與煤層距離增加而減小,當主關鍵層與煤層距離大于其臨界層位后便不再對支承壓力產(chǎn)生影響。(4)基于數(shù)值模擬的結果,采用線性回歸的數(shù)學分析方法提出了主關鍵層對支承壓力影響的預測模型,并應用到淮北海孜煤礦Ⅱ102采區(qū),得出該覆巖條件下最大采動影響范圍達到294.8m,Ⅱ1026機巷處于Ⅱ1024工作面回采后的應力集中區(qū),解釋了Ⅱ1026機巷發(fā)生動力災害的原因。
[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，

本文編號：2116382