程香港, 乔伟, 李路, 江传文, 倪磊. 煤层覆岩采动裂隙应力-渗流耦合模型及涌水量预测[J]. 煤炭学报, 2020, 45(8): 2890-2900. DOI: 10.13225/j.cnki.jccs.2019.0651
引用本文: 程香港, 乔伟, 李路, 江传文, 倪磊. 煤层覆岩采动裂隙应力-渗流耦合模型及涌水量预测[J]. 煤炭学报, 2020, 45(8): 2890-2900. DOI: 10.13225/j.cnki.jccs.2019.0651
CHENG Xianggang, QIAO Wei, LI Lu, JIANG Chuanwen, NI Lei. Model of mining-induced fracture stress-seepage coupling in coal seam over-burden and prediction of mine inflow[J]. Journal of China Coal Society, 2020, 45(8): 2890-2900. DOI: 10.13225/j.cnki.jccs.2019.0651
Citation: CHENG Xianggang, QIAO Wei, LI Lu, JIANG Chuanwen, NI Lei. Model of mining-induced fracture stress-seepage coupling in coal seam over-burden and prediction of mine inflow[J]. Journal of China Coal Society, 2020, 45(8): 2890-2900. DOI: 10.13225/j.cnki.jccs.2019.0651

煤层覆岩采动裂隙应力-渗流耦合模型及涌水量预测

Model of mining-induced fracture stress-seepage coupling in coal seam over-burden and prediction of mine inflow

  • 摘要: 矿井涌水量的预测是煤矿安全生产、防排水设计的重要依据,以往的矿井涌水量预测方法未考虑采动引起的覆岩裂隙渗透特性变化,预测结果与矿井实测涌水量相比误差较大。以陕西招贤煤矿1307工作面为研究区,基于覆岩采动粗糙裂隙面的渗流特性,对裂隙应力-渗流耦合计算模型进行了修正,提出了修正后的三维采动裂隙应力-渗流网络计算模型;基于覆岩导水裂隙带发育特征以及矿压实时数据开展了不同间距及隙宽组合的正交数值模型实验,结合修正后的裂隙应力-渗流网络计算模型,分析了覆岩采动渗透率的动态变化规律,并根据导水裂隙带发育趋势分段预测了工作面矿井涌水量。研究结果表明:上覆岩层受采动影响,应力场及渗透性发生改变,且渗流场的扰动范围与应力场相比较大,渗透性的变化在不同方向上具有差异性,渗透系数在水平方向上的影响范围小,变化量大。在垂向上的影响范围大,但变化量小。通过模型预计涌水量与实测涌水量对比发现,试验模型分层位间距为l1=10 m,l2=30 m,l3=150 m及隙宽组合b1=0.05 m,b2=0.01 m,b3=0.005 m时,较为符合研究区实际工程情况。最后,基于离散元软件裂隙渗流模型,结合模型间距及隙宽组合形式,对裂隙应力-渗流耦合计算模型的可靠性进行探讨,模拟结果与裂隙应力-渗流耦合模型计算的结果基本一致。

     

    Abstract: The prediction of mine inflow is an important basis for the coal mine safe production and waterproofingdrainage system design. The previous prediction methods did not consider the change of the overlying rock seepage characteristics caused by mining and the prediction results had large errors compared with the actual measurement.Taking the working face No. 1307 of Zhaoxian Coal Mine in Shaanxi Province as the research area,the authors modify the fracture stress-seepage coupling calculation model and propose a modified three-dimensional mining-induced fracture stress-seepage network calculation model on the basis of the seepage characteristics of the rough fracture surface of overburden caused by mining. Based on the development characteristics of water-conducting fractured zone and monitoring data of mine pressure,the orthogonal experimental model with different pitch and gap width combinations is designed. Using the modified three-dimensional mining-induced fracture stress-seepage network calculation model,the dynamic change pattern of mining permeability is discussed and the mine inflow is predicted according to the development trend of the water-conducting fractured zone. The results indicate that the stress field and permeability on the overlying strata changes due to the influence of mining,and the variation range of the seepage field is larger than the variation range of the stress field. The change of permeability is distinguished in different directions,and the influence range of the permeability coefficient in the horizontal direction is small and the amount of change is large. The range of influence in the vertical direction is large,but the amount of change is small. Comparing the predicted water inflow with the measured water inflow,the test model of stratification spacing is l1= 10 m,l2= 30 m,l3= 150 m and gap widthcombination is b1 = 0. 05 m,b2= 0. 01 m,b3= 0. 005 m,which is more accordance with the actual project situation of the research area. Finally,on the basis of the combination form of model distance and gap width,using the discrete element software fracture seepage model,the reliability of the fracture stress-seepage coupling calculation model is discussed. The simulation results are basically consistent with the fracture stress-seepage coupling model.

     

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