【作者】 李忠建；

【导师】 魏久传；

【作者基本信息】 山东科技大学 ， 地质工程， 2011， 博士

【摘要】 针对在半胶结低强度条件下,浅埋煤层开采造成的覆岩运动和顶板水害评价问题,本文以新疆伊犁一矿试采区为研究对象,根据研究区钻探资料、地球物理探测资料、岩石物理力学性质试验资料等,采用理论分析、数值模拟、相似材料物理模拟、室内试验等方法,对研究区覆岩地层结构特征、覆岩运动规律、顶板结构稳定性、关键隔水层隔水性能、煤层顶板水害评价、防治水主要技术途径等方面进行了探索性研究,主要研究成果如下：(1)系统分析了研究区主采煤层顶板含水层厚度变化规律、岩性特征、富水性与导水性特征；隔水层厚度变化规律、岩性特征；煤系各含水层间的水力联系等。分析了第四系底部富水性与导水性特征,指出第四系孔隙含水层是煤系含水层的主要补给水源。(2)通过离散元数值模拟、有限元数值模拟以及相似材料物理模拟,研究了不同采高条件下,5煤层开采覆岩运动规律。模拟结果表明：随着采高的加大,研究区发生切顶冒落危险性增加。采用“短砌体梁”结构理论和“台阶岩梁”结构理论对研究区5煤顶板结构稳定性进行了评价,依据半胶结低强度围岩特点,提出用“半-低”滑落系数修正其评价体系,评价结果与试验所得结论较为一致。(3)对覆岩分带特性进行了分析,提出了研究区的覆岩分带特性两种划分依据,即分别为“半-低”四带和“半-低”两带。通过分析裂缝闭合带与时间之间的关系,给出了裂缝闭合带的计算方法。(4)探讨了关键隔水层的概念及确定方式。分析了关键隔水层的厚度变化特征、岩性特征；通过膨胀试验、崩解试验、软化试验、拉伸试验及单轴压缩试验等对关键隔水层进行了物理力学分析。通过岩石力学、三轴应力渗透试验等,评价了关键隔水层的隔水性能。提出了“隔水指数”法,并用于定量评价关键隔水层的隔水性能,根据评价结果,研究区大部分区域处于中等隔水性区。(5)依据5煤顶板含水层厚度变化特征及岩性组合特征,在考虑煤层顶板的岩性及结构特征对富水性影响的基础上,提出了“富水指数”法来定量评价煤层顶板含水层富水性,并划分了富水性分区。通过室内试验预计、规程公式预计、多元线性统计预计和变形预计四种方法对导水裂缝带高度进行预计。在考虑煤层顶板的岩性及结构特征对于隔水层的影响的基础上,采用“隔水指数”法评价了煤层顶板隔水层隔水性能,并划分了隔水性能分区。(6)在综合分析顶板突水影响因素的基础上,利用“五图信息融合”法预测了顶板突水危险性。并采用VB6.0开发了相应的工作面顶板突水危险性预测软件。根据研究区5煤顶板含水层赋存情况,分别用大井法和比拟法预计了5煤顶板涌水量。计算了5煤开采上限。(7)分析了研究区充水条件,提出了研究区防治水技术途径与措施。更多还原

【Abstract】 In the conditions of semi-cementation and low strength, coal mining may bring many problems, such as overburden strata movement and evaluation of roof water disaster. To solve these problems, we took the first coal mine of Yi-Li as study object. Based on the drilling data, geophysical exploration data and physical mechanics test data of rock in study area, we used many methods, such as theoretical analysis, numerical simulation, similar material physical simulation and laboratory test, to have exploratory study on many aspects. And they were structure characteristics of overburden strata, overburden strata movement law, roof structural stability, water resisting capability of key aquifuge, roof water disaster evaluation, main technical ways of roof water prevention and control in study area. The main study results was as follows:(1)We systematically analyzed the primary mineable coal seams’roof aquifer thickness variational law, lithological characteristics, water abundance and conductivity characteristics. We also analyzed the aquifuge thickness variational law and lithological characteristics. And we analyzed the hydraulic connection of the aquifers during coal measures. We had analysis of the water abundance and conductivity characteristics of the quaternary bottom. The Quaternary pore aquifer was the main recharge source aquifers during coal measures.(2)We had studied on mining overburden strata movement law of the 5th coal seam under different conditions by many methods, such as discrete element numerical simulation, finite element numerical simulation, and similar material physical simulation. The simulation results showed that with the increase of mining height, the cutting roof caving risk increased. We used both the short voussoir beam theory and step beam theory to evaluate the 5th coal seam roof structural stability. According to the characteristics of semi-cementation and low strength, we put forward "semi-low" slide coefficient to modify the evaluation system. The result was coincident with the test.(3)On analysis of the overburden strata zoning, we held that the overburden zoning characteristics had two conditions in study area, and they were "semi-low" four zones and "semi-low" two zones. On the analysis of the relationship between fissure closure zone and time, we gave the calculation method of the fissure closure zone.(4)We discussed the concept of key aquifuge and determination ways. We had analysis of the key aquifuge thickness variational law and lithological characteristics. Moreover, we had analysis of physical and mechanical properties to the key aquifuge by swelling test, disintegrating test, softening test, tensile test, uniaxial compression test and so on. And we also evaluated the key aquifuge water resisting capability by rock mechanics test and triaxial stress-permeability test. To quantitatively evaluate the water resisting capability of key aquifuge, we put forward the water resisting index method. The results showed most study area were in middling water resisting capability partition.(5)According to the 5th coal seam’s roof aquifer thickness variational characteristics and lithological association characteristics, and considering the influence of roof lithology and structural characteristics to water abundance, we put forward the water abundance index method to have quantitative evaluation of the coal seam roof aquifer water abundance. Moreover, we divided the water abundance partition. The height of water flowing fractured zone was predicted by four methods. They were laboratory test prediction, regulation formula prediction, multi-linear statistical prediction and deformation prediction. Based on considering the influence of roof lithology and structural characteristics to aquifuge, we used the water resisting index method to quantitative evaluate the water resisting capability of the roof aquifuge and we divided the water resisting capability partition.(6)Based on the comprehensive analysis of factors affecting roof water inrush, we put forward "five maps" information fusion method to predict roof water inrush risk. And we developed the corresponding roof water inrush risk prediction software by VB6.0. According to the 5th coal seam roof aquifer condition in study area, we used two methods to predict the roof water inflow, and they were big well method and analogy method. We calculated the upper mining limit of the 5th coal seam.(7)Finally, we had analysis of the water filling conditions, and put forward technical ways of roof water prevention and control in whole study area.更多还原