浅埋非均质地质、单一关键层工作面动载系数预测模型与工程验证

Prediction model of dynamic load coefficient for shallow-buried heterogeneous geological and single key stratum working faces and its engineering verification

  • 摘要: 神东矿区浅埋煤层地质条件具有显著非均匀性,采用传统平均动载系数法进行液压支架选型时,难以准确反映实际载荷分布,易造成支架工作阻力设计偏差,诱发支架–围岩系统失稳,制约工作面安全高效开采。研究以哈拉沟煤矿22309工作面为背景,旨在揭示非均匀地质条件对动载系数的控制机制,建立适用于该条件的动载系数预测模型,为液压支架合理选型提供理论依据。 研究采用现场实测与理论分析相结合的方法。通过分析不同分段基岩厚度与埋深对动载系数的影响规律,评估支架适应性差异。基于能量等效原理,结合“浅埋、单一关键层”地质特征,将主关键层破断回转释放能量等效为动载源,构建融合埋深、推进长度与基岩厚度等参数的动载系数预测模型(DP模型),并采用Levenberg-Marquardt算法对模型参数进行辨识。 结果表明:22309工作面动载系数呈梯阶分布,首段为1.10,次段为1.21,导致次段支架安全阀开启率较首段提高5.5%。DP模型对首段和次段动载系数的预测误差分别为8.95%和1.59%,精度较传统方法提升8.14%和4.86%。在22315工作面应用中,预测动载系数为1.202,与实际误差0.98%,据此计算出支护阻力为10165.2 kN,选用ZY12000/25/50D型液压支架。现场监测证实支护系统运行稳定。 研究构建的DP模型能够基于常见地质参数有效预测浅埋煤层非均匀条件下的动载系数分布,物理意义明确、预测精度高,克服了传统平均动载方法的不足。

     

    Abstract: The shallow-buried coal seams in the Shendong mining area exhibit significant geological heterogeneity. When the traditional method based on an average dynamic load coefficient is used for hydraulic support selection, it fails to accurately reflect the actual load distribution, which may result in inappropriate design of working resistance, induce instability of the support–surrounding rock system, and restrict safe and efficient mining. Taking the 22309 working face of Halagou Coal Mine as the engineering background, this study aims to reveal the controlling mechanism of geological heterogeneity on the dynamic load coefficient and to establish a prediction model suitable for such conditions, providing a theoretical basis for rational hydraulic support selection. Field measurements and theoretical analysis were combined in the research. The influence of bedrock thickness and burial depth in different sections on the dynamic load coefficient was analyzed, and the adaptability differences of hydraulic supports under varying geological conditions were evaluated. Based on the energy equivalence principle and the geological characteristics of “shallow-buried, single key stratum,” the released energy from the rotation of the fractured key stratum was treated as the dynamic load source. A dynamic load coefficient prediction model (DP model) integrating burial depth, advancing length, and bedrock thickness was established, and the Levenberg–Marquardt algorithm was applied to identify the model parameters. The results indicate that the dynamic load coefficient of the 22309 working face presents a stepped distribution, with 1.10 in the first section and 1.21 in the second section, leading to a 5.5% higher safety valve opening rate in the latter. The prediction errors of the DP model for the two sections were 8.95% and 1.59%, respectively, with prediction accuracy improvements of 8.14% and 4.86% compared with the traditional method. When applied to the 22315 working face, the predicted dynamic load coefficient was 1.202, with only 0.98% error relative to the measured value. The required support resistance was calculated as 10165.2 kN, and the ZY12000/25/50D hydraulic support was selected accordingly. Field monitoring confirmed the stable operation of the support system. The DP model can accurately predict the distribution of dynamic load coefficients in shallow-buried coal seams under heterogeneous geological conditions using commonly available geological parameters. It has clear physical significance, achieves high prediction accuracy, and overcomes the limitations of the traditional average method.

     

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