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分类号密级UDC编号采空场覆岩变形特性研究姓名:指导教师姓名、职称:学科、专业名称:研究方向:年 月The Behavior Study of Overburden deformation in Abandoned Stope郑 重 声 明本人的学位论文是在导师指导下独立撰写并完成的,学位论文没有剽窃、抄袭、造假等违反学术道德、学术规范和侵权行为,本人愿意承担由此产生的法律后果和法律责任,特此郑重声明 学位论文作者(签名):年 月 日3 摘 要随着人们对矿产资源的需求越来越大,采空区规模及开采深度也不断加大,由此引起的覆岩及地表变形问题也越来越严重,由此严重影响着人们的生产生活,并带来巨大的经济损失。因此对地下开挖引起的覆岩变形破坏过程与机理、地表变形规律等问题进行研究具有很强的现实意义。覆岩变形与地表沉降具有非均匀、非连续与大位移的特点,是一个高度复杂的非线性问题。前人在这方面已经做了大量的工作,分别采用现场监测、理论分析、室内试验及计算机模拟等手段,对覆岩与地表变形的预测、裂隙和离层的分布以及由此带来的采动损害的防护与控制等问题进行了广泛的研究,得出了许多有益的经验与结论。本论文结合横向课题“湖北荆襄化工集团大峪口矿段木架山采空场处理研究”,对覆岩变形进行了一系列研究。主要内容及其结论如下:1)对覆岩变形及地表沉降引发的灾害问题进行了全面而系统的调研分析,综述了目前主要的覆岩变形与地表沉降的分析手段与研究进展,特别回顾了相似模拟的研究现状及其优缺点,为论文的研究提供了基础。确定了采用有限元数值模拟与相似材料模拟作为研究木架山采空区覆岩变形特性研究手段的方案。2)进行了现场地质条件勘查,开展了室内单轴压缩、劈裂与三轴剪切岩石力学参数试验,结合现场经验与前人研究成果,提出了数值模拟与相似模拟研究所需要的岩体力学参数。3)采用有限元ANSYS软件分析了覆岩与地表的移动、变形与破坏的规律与顶板的极限跨度,尝试了离层得模拟。研究发现,随着矿柱的崩落,覆岩跨度不断增加,引起的地表移动范围也不断增大,地表垂直沉降范围大致为跨度的1.51.7倍,垂直沉降曲线始终关于最大沉降点对称;水平移动的范围大于垂直沉降的范围,最大水平移动量大约为最大沉降量的40,且水平移动不对称。另外,当覆岩发生整体下沉时离层主要存在于跨度两端,离层由层理剪切破坏引起。4)采用正交试验确定相似模拟试验中的材料配比,用云母粉模拟广泛存在于岩层中的层理,模拟了覆岩从变形到开裂、跨落的全过程,描述了离层的产生过程与存在范围,分析了地表沉降规律,得出了较为可靠的覆岩极限跨度:110m。并对试验中存在的测量误差,材料参数误差进行了分析。5) 通过对木架山矿区覆岩变形规律的研究,我们发现,不论是地表沉降,还是覆岩内部的变形破坏,数值模拟与相似模拟结果基本是一致的,并对层理的破坏模式与机理进行了深入研究。在全面了解主要的沉降预防与治理措施的基础上,对类似工程的覆岩变形提出了可行的控制方案。关键词:覆岩变形;数值模拟;相似模拟;层理;离层;沉降控制ABSTRACTThe mining deep and the scale of abandoned stope is continuously augmenting as the demand for mineral resources increase more and more for satisfying the need of human development, which lead to the deformation of overburden and subsidence of earth surface are more and more serious. It put sorely impact on the peoples life and production action, at the same time it cause heavy economic losses. Wherefore, it is of practicability that study the rule and mechanism of overburden deformation and earth surface subsidence caused by underground mining.The characteristics of overburden deformation and surface subsidence is non-uniform、discontinuity and large displacement, so this is a exceeding complicated non-linear problem. Our predecessors have adopted some methods, for example, monitoring in-situ、theory analysis、laboratory test and computer simulation etc, to forecast the of overburden deformation and subsidence of earth surface, to study the distributing of cranny and layer separation and to discuss the defend and control scheme of overburden deformation, many instructive experience and conclusions have been got.The paper carried through a series of study about overburden transmutation based on the project” Study of Abandoned Stope Disposal of Dayukou Ore of Mujiashan of Jingxiang Chemical Engineering Company of HuBei ”. The main content and conclusion of this paper are following:1)Comprehensive and systemic investigation and analyses on disasters caused by overburden deformation and earth surface subsidence were carried out. Recent main analyses methods and study development are summarized, especially, the development situation of similarity simulation and its merits and shortcomings were reviewed, which provide a foundation for this thesis. So, the scheme that adopt FEM numerical simulation and similarity simulation to study deformation behavior of abandoned stope overburden was confirmed.2)Laboratory uniaxial compression tests、split tests and confined shear tests were conducted to obtain the rock mechanical parameter. Combine the practice experience and acquired production, the rock -mass mechanical parameters necessary for numerical simulation and similarity simulation were established.3)The deformation and breakage rule of overburden and earth surface、the limit span of roof are analysed by FEM ANSYS software, an attempt is made to simulate the layer separation in overburden in FEM numerical modeling. It has been found from this research that the range of surface movement increases moderately with the collapse of jambs and the increase of the roof span. The subsidence area ranges from 1.5 times to 1.7 times of the roof span and the subsidence curves are symmetrical to the vertical line through the point with maximum subsidence. The horizontal movement, however, is not symmetrical and its impacting area is larger than the range of subsidence, with its maximum value equal to 40% of the maximum subsidence. In addition, the layer Separation exist in the end of span of overburden if the subsidence happen in whole overburden,which is resulted from the shear failure of the bedding plane.4)Orthogonal experiments was adopted to determine material proportion of similarity simulation, the stratification widely in stratum was modeled by mica powder. The whole process from deformation to crack and collapse of ov
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