淮北许疃矿抽采后瓦斯含量损失影响因素分析及预测

Influencing factors analysis and prediction of the loss of gas content after gas drainage in Xutuan Mine of Huaibei,China

  • 摘要: 抽采后残余瓦斯的存在对于矿井生产依然具有危险性,研究残余瓦斯的赋存规律及其预测是十分必要的。分析了淮北煤田许疃煤矿3233采区地质条件,通 过断层分维、煤层底板构造曲率和煤层倾角等指标的计算和统计,并分别赋予0.35,0,35和0.30的权重,计算得到研究区的构造指数及其分布,根据选取的42组数据,讨论了构造指数 、煤层埋深、煤厚和原煤瓦斯含量等影响因素对抽采残余瓦斯赋存的影响,运用多元线性回归方法,拟合了瓦斯含量损失与构造指数、煤层埋深、煤厚等影响因素指标之间的相关 关系,运用BP人工神经网络模型研究了预测抽采后瓦斯含量损失的可行性。结果表明:构造指数可以更精确地定量表征矿井构造复杂程度。瓦斯含量损失的主要影响因素为构造指数 、煤层埋深、煤厚和原煤瓦斯含量。瓦斯含量损失总体上与构造指数呈负相关,而与其他因素的指标均呈正相关。经过数理统计的F检验,F=20.82>F0.01(3,38)=4.35,故多元线性回 归的结果是显著的,表明瓦斯含量损失与各影响因素指标之间具有较密切的内在联系,其中构造指数对瓦斯含量损失的影响程度最大,煤层埋深影响程度最小,煤厚的影响程度介 于构造指数与煤层埋深之间。以瓦斯含量损失为输出指标,以构造指数、埋深、煤厚和原始瓦斯含量为输入指标,建立了4×10×1结构的BP人工神经网络模型,模型经过学习训练后 预测精度高,相对误差为1.19%~1.34%,表明可以运用人工神经网络模型预测未采区抽采后的瓦斯含量损失,残余瓦斯含量即为原煤瓦斯含量减去瓦斯含量损失,故可以间接预测 抽采后残余瓦斯含量。

     

    Abstract: After raw coal gas was extracted from coal seam,the danger of gas outburst cannot be eliminated completely. Therefore,the occurrence law of residual gas after extraction and its prediction must be studied. The geological con-ditions of mining area No. 3233 in Xutuan coal mine in the Huaibei coal field,China,were analyzed. The structural in-dex and its distribution in the study area were evaluated according to the calculation and statistics of fractal dimension of faults,the structural curvature of coal seam floor and dip angle of coal seam,and their giving weights of 0. 35,0. 35, and 0. 30. The influence of structural index,coal seam depth,coal thickness and raw coal gas content on residual gas after extraction was analyzed by using 42 sets of selected data. The correlation between the loss of gas content (LGC) and influencing factors,e. g. ,structural index,coal seam depth,and coal thickness,was fitted through multiple linear regressions. The feasibility of predicting LGC after extraction was studied by using the back propagation (BP) artificial neural network model. Results show that the structural index can quantitatively and accurately characterize the struc-tural complexity of the mine. The LGC is mainly influenced by structural index,the buried depth of coal seam,coal thickness,and raw coal gas content. In general,LGC is negatively correlated with structural index and positively corre-lated with other influencing factors. According to the F-test of mathematical statistics,i. e. ,F = 20. 82>F0. 01(3,38)= 4. 35,the results of multivariate linear regression is significant,indicating a close internal relationship between the LGC and the indexes of the influencing factors. Among these aspects,the structural index has the greatest influence on LGC,whereas the burial depth of coal seam has the least influence. The influence of coal thickness is between that of structural index and the burial depth of coal seam. A BP artificial neural network model with 4×10×1 structure was es-tablished with LGC as the output index and the structural index,the buried depth of coal seam,coal thickness and raw gas content as the input indicators. The accuracy of model prediction results is high after learning and training,and the relative error is 1. 19% -1. 34% ,indicating that the artificial neural network model can be used to predict LGC after extraction in the unmined area. Residual gas content is the original coal gas content minus the LGC. Hence,this value can indirectly predict the residual gas content after extraction.

     

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