【作者】 许柏青；

【导师】 张发旺；

【作者基本信息】 石家庄经济学院 ， 地下水科学， 2015， 硕士

【摘要】 采矿过程中,上部岩层中的应力平衡被打破,发生了岩层的离层、变形和破断,含水层和隔水层中的裂隙发生了变化,使得原来的隔水层成为了导水通道或储水空间。隔水层中的裂隙演变,改变了原有的含水层组合关系,在局部地区导通了上下含水层,使得原有的含水层结构发生了变化;另外,两个采面间的含水层结构由于安全煤柱的存在而与采空区的变化不尽相同。这些变化以往注重从突水的角度进行研究,而从含隔水性质的转化的角度研究甚少。本文主要研究采煤引起上覆岩层破坏及其中的含水层结构变异情况,采用野外地质调查、地球物理现场勘查、室内相似材料模拟试验、计算机数值模拟、理论分析等一系列研究方法,以潞安集团余吾矿区为研究区,研究了采煤引起上覆岩层中的裂隙演变及其对含水介质导水能力的影响,重点研究了两个工作面间交互带有叠加效果时导水裂隙带的发育及其对含水层结构的影响。论文取得的主要研究成果如下:1.通过地球物理勘查发现,采动后煤层上覆地层跨落、塌陷,地层结构变得紊乱,煤层顶板以上100m的范围地层破坏比较严重。在保留煤柱的上方,没有发生跨落,上方相对采空区隆起。圈定的导水裂隙带侧向边界超出采空区的范围,说明采动裂隙侧向有延展。在两个采面间,导水裂隙带的高度要比单个工作面的导水裂隙带高度大2.通过相似材料模拟实验研究认为垂直于煤层剖面上,开切眼及工作面附近的裂隙较为发育,采空区中部裂隙由于上覆岩层的重力作用被压实,边界裂隙分布密度约为采场中央重新压实区的2~4倍,呈椭抛带状分布。两个工作面侧向裂隙发育不甚明显,监测点位移从下到上逐渐减小。3.通过计算机模拟研究认为,采空区中部裂隙相对压实,其两侧以垂向裂隙发育为主,顶部以离层裂隙发育为主,这一结论与相似材料模拟实验结果一致。研究认为,裂隙发育不仅在采空区上方发育,而且向采空区侧方延展,延展到了煤柱上方一定的距离,根据本次研究结果延展的距离距采空区大约为33.5米;模拟结果认为当两个工作面之间有叠加作用时,其中的导水裂隙带的高度比单个工作面的导水裂隙带的高度要大。这一结论与野外地球物理分析结果一致。4.通过相似材料模拟实验、计算机数值模拟和地球物理勘查三种方法比较,最终认为,研究区单个工作面中导水裂隙带高度约为101米,其横向延展距离距采空区边界约为33.5米;两个采面有叠加作用时,保留煤柱上方对应的导水裂隙带高度约为130米。5.研究认为,由于采动影响,含水层本身以及含水层之间非均质性发生了变化。原来的隔水层由于采动裂隙的存在也变成为有空隙或裂隙的导水通道或储水空间,使得原来两个水力联系很弱的含水层而变成水力联系很强的统一的含水层,从而构成了新的含水层。这个新的含水层其中的裂隙发育从下到上存在明显的分带性,从外到内存在着明显的分区性,并且其储水能力和含水层的规模也变大。从结构上看,原来两个相对水平的单一含水层,在采空区上方,变成一个“复合式”含水层。从含水层空间展布来说,原来水平的含水层演变成局部成“蜂窝状”的含水层。更多还原

【Abstract】 The balancing of stresses of overlying strata is broken in mining process and it results to the separation,deformation and fracture of stratum.As a result,fracture between aquifers and aquiclude changes,so that the original aquiclude becomes a water passage or storage space.With the evolution of aquiclude’s fracture,the composition relationships of original aquifers would be changed,which will lead to the changes of aquifer structures.Besides,due to the barrier pillar,the aquifer structure between two working faces is not similar to the changes of gob.Previous studies on these changes often starts from the point of water inrush and little of them have researched from the property variation of aquiclude.Through studying the overlying strata destruction caused by coal mining and the structure variations of the aquifer,this thesis adopts a series of research methods including field geological investigation,geophysical field investigation,indoor simulation experiment,computer numerical simulation and theoretical analysis to study the fracture evolution of aquiclude and its influences on water conductivity of aquiferous medium.It takes Yuwu Coal Mine of Shanxi LuAn Mining Group as research district and focuses on studying the fracture evolution of water-conducting zone when the mutual contact zones between two working faces superpose with each other and its influences on aquifer’s structure.The main research results are as follows:1.Through geophysical field investigation,w discover that overlying strata will fall,subside after mining and strati-graphic structure would become disorganized.Besides,the 120 mm strata destruction above coal roof is serious.There is no falling above the keeping coal pillar and goaf rises.The transverse border of circled water-conducting fracture zone is larger than the scope of goaf,which indicates that mining fracture has extended.Between two working faces,the height of water-conducting fracture zone is higher than that of a single face.2.Through indoor simulation experiment,this research thinks that fractures which are perpendicular to coal seam profile and closed to open-off cut and working face are well developed.The middle fracture on goaf is compacted by gravity action of overlying strata.The distribution density of boundary fractures is two to four times of middle face recompaction area and it is distributed in elliptic paraboloid zone.The lateral fracture between two working faces does not develop and monitoring point’s displacement decreases from the bottom up.3.Through computer numerical simulation,this research discovers that the middle fracture of goaf has higher degree of compaction.Its two sides is based on vertical fracture development and its top part is based on abscission fracture development,which is in accord withindoor simulation experiment.According to this research,fractures develop not only above the goaf but also extend to the above of coal pillar.This study found that the extended distance of goaf is about 33.5 meters.And according to simulation result,the height of water-conducting fracture zone is higher than that of a single face,which conforms with the analysis result of geophysical field investigation4.Through indoor simulation experiment,computer numerical simulation and geophysical field investigation,this research thinks that the height of water-conducting fracture zone in single face is 101 meters and its lateral extended distance is 33.5 meters away from goaf area.When two working faces superpose with each other,the height of water-conducting fracture zone above the coal pillar is about 130 meters.5.According to research,influenced by mining activities,the anisotropy in aquifer itself and between aquifers changes.Due to the existence of mining fractures,previous aquiclude becomes water passage or storage space,making previous aquifers with low hydraulic connections become united aquifers with high hydraulic connections.The fracture development of the new aquifer shows zonation from bottom up and clear partition from outside to inside.Besides,its storage capacity and the size of the aquifer becomes larger.From the structural point of view,the aquifers in relative level become an aquifer above the goaf.From the point of aquiter structure distribution,previous horizontal aquifer evolves into alveilate aquifer.更多还原