彬长矿区煤层采动导水裂隙带高度RF-BP模型预测对比研究

    Comparative study on RF-BP model prediction of mining water-conducting fracture zone height in Binchang Coal Mine

    • 摘要: 西部黄陇侏罗系煤田煤层赋存条件一般较厚,其中彬长矿区煤层厚度平均大于5 m,最厚可达14 m,且常采用综放开采工艺,造成煤层顶板导水裂隙带发育厚度大且发育规律不明,矿井涌水量居高不下,严重影响矿区安全生产。为研究彬长矿区煤矿工作面开采扰动覆岩而导致的煤层顶板导水裂隙带发育高度,优选了煤层开采厚度、煤层埋深、顶板覆岩岩性、顶板构造特征、开采速度、工作面长度、采煤工艺等7个影响因素,通过AHP层次分析法分别计算出了上述各影响因素的权重,发现煤层开采厚度、工作面长度2个影响因素所占权重相对较大;通过Matlab对搜集的数据进行插值,使数据分布更为平滑;通过反向传播神经网络(BP)、遗传算法优化神经网络(GA-BP)、粒子群优化算法优化神经网络(PSO-BP)、随机森林(RF)算法对插值后数据进行回归拟合。研究发现,4种方法对原始数据的拟合效果都较好,其中随机森林RF相对其他模型对原始数据的拟合具有更高的准确度,训练集和测试集的均方根误差RMSE分别为0.037 41和0.055 16,决定系数R2分别为0.987 37和0.957 89。研究结果可为彬长矿区煤矿开采导水裂隙带发育高度的预测提供一定的参考。

       

      Abstract: The occurrence conditions of coal seams in western Huanglong Jurassic coalfield are generally thick, of which the average thickness of coal seams in Binchang Mining Area is greater than 5 m, and the thickest coal seam can reach 14 m, and the fully mechanized caving technology is often adopted, resulting in large thickness and unclear development law in the water-conducting fracture zone of coal seam roof, and high water inflow in the mine, which seriously affects the safety production in the mining area. In order to study the development height of seam roof water-conducting fracture zone caused by disturbed overlying rock mining in Binchang Coal Mine, seven influencing factors such as the thickness of coal seam, seam buried depth, roof overlying rock lithology, roof structure characteristics, mining speed, the length of working face and mining technology were first selected. Firstly, the weight of the above influencing factors is calculated by AHP, and it is found that the weight of the two influencing factors, the thickness of coal seam and the length of working face, is relatively large. The collected data is interpolated by Matlab to make the data distribution smoother. Back propagation neural network, genetic algorithm and particle swarm optimization were used to optimize BP neural network and random forest algorithm to carry out regression fitting for the interpolated data. It is found that the four methods have better fitting effect on the original data, and random forest RF has higher fitting accuracy than the other models. The root mean square errors (RMSE) of the training set and the test set are 0.03741 and 0.05516, and the determination coefficient R² is 0.98737 and 0.95789, respectively. The research results can provide some references for predicting the development height of the water-conducting fracture zone in Binchang Coal Mine.

       

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