【作者】 许勃；

【导师】 邓广哲；

【作者基本信息】 西安科技大学 ， 采矿工程， 2009， 硕士

【摘要】 随着煤炭资源开采强度的不断加大,急倾斜煤层的开采越来越受到关注。急倾斜煤层开采覆岩破坏规律及导水裂隙带高度的研究是西部煤炭开采的重大课题,特别是对于河流、岩溶水、老窑积水以及降雨入渗影响的急倾斜煤层开采。本文以云南圭山煤矿急倾斜煤层顶板为研究对象,在导水裂隙带高度的计算中采用一种新思路,将受孔隙水压影响的顶板砂岩引入到急倾斜煤层覆岩顶板的模拟计算中,分析了急倾斜煤层在受孔隙水压影响下顶板覆岩力学性质发生改变时的导水裂隙带发育高度。首先,通过煤层顶板砂岩F-RFPA^2D数值模拟试验,对有孔隙水压和无孔隙水压作用下岩石的整个破坏过程进行了详细分析,得出了岩石全应力应变全程曲线。并对相同应力条件不同孔隙水压下岩石的破坏情况进行了模拟,得出岩石破坏强度与孔隙水压之间的函数关系曲线,通过曲线拟合得出曲线拟合方程;其次,运用材料力学、弹性力学、断裂力学知识,结合数值模拟试验对岩石中孔隙水压的物理化学作用及力学作用原理进行了分析,讨论了孔隙水压对砂岩力学参数的影响,重点分析了孔隙水压对岩石强度以及破坏模式的影响,揭示了孔隙水压引起覆岩导水裂隙带高度变化的机理;最后,结合急倾斜煤层覆岩破坏理论提出了孔隙水压对急倾斜煤层覆岩移动特征以及破坏结构的影响;通过对云南圭山煤矿急倾斜煤层31139工作面进行FLAC^3D数值模拟分析,得出由于孔隙水压的影响,导致覆岩破坏规律以及导水裂隙带发育高度呈现出与无孔隙水压时不同的特征。运用急倾斜煤层导水裂隙带高度经验公式以及现场观测数据与模拟结果进行对比,验证了数值模拟结果的正确性。最后对不同分段高度下覆岩导水裂隙带高度进行模拟研究,论证了在该地质条件下70m分段高度有利于工作面回风巷安全生产管理。并运用回归分析理论对模拟结果进行曲线拟合得出2MPa孔隙水压下分段高度和导水裂隙带高度的拟合方程。更多还原

【Abstract】 China is one of the countries which have the world’s most abundant coal resources. With the strength of the coal mining increased,steep seam mining are attracting increasing attention. The study of surrounding rock deformation and water flowing fractured zoneheight of the steep seam mining is a major issue of the Western coal mining. Especially for the steep seams which are under the rivers,karst water,old kiln water and impacted by the surface water infiltration in the rainy season. Mine water hazard prevention and control is a serious problem that can not be ignored on mine safety production. This paper studies YunNan guishan steep seam,on the basis of participation tutor’s subject of research on complex coal mining, using a new method study the overburden failure law and water flowing fractured zone height of the steep seam mining under pore water pressure that caused by rainfall.First, using F-RFPA^2D numerical simulation of sandstone aquifer of the coal seam roof, detailly analyzed the whole failure process of rocks under pore pressure and no pore pressure. Obtained the whole process of stress-strain and permeability curves of the of rock. Simulated the rock damage under the same confining pressure and different pore pressure, got the curve between the rock damage strength and the porosity pressure curve. Through the curve fitting obtained the curve equation;Secondly, using material mechanics elastic mechanics and fracture mechanics, analyzed the physical chemistry effection and mechanical principle effection of pore pressure. Discussed the effection of pore pressure on the mechanical properties of sandstone, emphatically analyzed pore pressure’s effection on rock failure mode. Reveals the mechanism of the overburden rock water flowing fractured zone height changes caused by water pore pressure.Finally, using the results of these studies, combination of steep seam overburden failure theory, puts forward the influential action of the pore pressure to the cover rocks movement features and the failure structureof steep seam ,and the mining working face 31139 were analyzed with a numerical simulation soft of FLAC^3D.Research suggests roof rock strength and deformation modulus has been changed as impact of pore-water pressure. These changes caused different failure law of overburden and hydraulic conductivity fracture zone height compared with no pore pressure. Using the water flowing fractured zone height empirical formula of steep seam and field observation data proved the correctness of the simulation results without pore pressure. At the same time, proposed there is a certain difference between rempirical formula and the actual result that consided the pore pressure. Applicated the theory to simulated the rock damage conditions of different sub-cover hight and demonstrated the height of 70m sublevel under the geological conditions is beneficial to face safe production.And using the regression analysis theory analysed the simulation results, obtained the fitting equation of sublevel height and overburden water flowing fractured zone height under the 2MPa pore pressure.更多还原