老三沟煤矿特厚煤层开采覆岩渗透性演化规律研究

发布时间：2018-12-14 08:13

【摘要】：本文基于老三沟煤矿的地质条件,开展了特厚煤层开采覆岩渗透率演化规律的研究,通过典型岩样不同应力路径条件下的渗透率测试,得出了老三沟煤矿典型岩样渗透率与体积应变的关系,构建了老三沟煤矿不同开采参数下的覆岩渗透性演化规律数值模拟计算模型。取得的主要成果有:(1)开展了典型含水层、隔水层岩样全应力-应变、采动应力路径和峰后加卸载路径的渗透率测试实验。全应力-应变过程中典型岩样渗透率随着轴向位移的增大,均表现出先下降再上升的趋势;采动应力路径下岩石的渗透率持续上升,围压对于渗透率的变化有较大影响;峰后加卸载路径下岩样渗透率与围压有较大的关系,渗透率随围压的降低而增大。(2)利用高斯函数拟合出了老三沟煤矿覆岩典型岩样渗透率-体积应变的关系方程。依此构建了典型岩样全应力应变过程数值模拟计算模型,并通过对比实验数据校核了相关参数的有效性。(3)研究了老三沟煤矿特厚煤层不同开采厚度下覆岩渗透率演化规律。研究表明:(1)采厚越大,覆岩渗透率增大区面积也越大,渗透率最大值也越大。采厚为10m和20m时渗透率增大区面积分别是采厚5m时的2.78倍和8.98倍。隔水层处渗透率最大值的数值增大,10m和20m采厚时隔水层处渗透率最大值分别是5m采厚时渗透率最大值的1.29倍和3.81倍;(2)距离煤层越远,采厚增加对岩层渗透率和体积应变的影响减小。
[Abstract]:Based on the geological conditions of Laosanggou coal mine, the evolution law of overburden permeability in thick coal seam mining is studied in this paper, and the permeability is tested under different stress paths of typical rock samples. The relationship between permeability and volume strain of typical rock samples in Laosanggou coal mine is obtained, and a numerical simulation model for the evolution of overburden permeability under different mining parameters is established. The main results are as follows: (1) the tests of the permeability of typical aquifer, water-separated rock sample, mining stress path and post-peak loading and unloading path have been carried out. In the process of total stress-strain, the permeability of typical rock samples decreases first and then increases with the increase of axial displacement, the permeability of rock increases continuously under the mining stress path, and the confining pressure has a great influence on the change of permeability. The permeability of rock samples under post-peak loading and unloading path is related to the confining pressure, and the permeability increases with the decrease of confining pressure. (2) the relationship between permeability and volume strain of typical overburden rock samples in Laosangou Coal Mine is fitted by using Gao Si function. Based on this model, a numerical simulation model of typical rock samples is established. The validity of related parameters is verified by comparing experimental data. (3) the evolution of overburden permeability under different mining thickness in Laosanggou coal mine is studied. The results show that: (1) the larger the mining thickness, the larger the area of overburden permeability and the larger the maximum permeability. When the mining thickness is 10 m and 20 m, the area of the increased permeability area is 2.78 times and 8.98 times of the mining thickness of 5 m, respectively. The maximum permeability of water separation layer increases, and the maximum permeability at 10m and 20m mining thickness is 1.29 times and 3.81 times as high as the maximum permeability at 5m production, respectively. (2) the longer the coal seam is, the smaller the influence of mining thickness on permeability and volume strain is.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD823.254

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