【作者】 刘金海；

【导师】 冯涛； 彭文斌；

【作者基本信息】 湖南科技大学 ， 采矿工程， 2006， 硕士

【摘要】 依托湖南省科技计划重点项目“南方煤矿绿色安全开采技术体系研究”,以条带开采和离层注浆减沉技术为基础,通过理论分析、数值模拟和工程实例验证等研究手段,研究了覆岩离层注浆与条带开采耦合提高回采率和减沉效果的技术体系。根据煤系地层的结构特征和顶板覆岩的运动特征,将整个覆岩结构视为两端固定的组合介质梁,考虑到覆岩各层之间物理力学性质的差异,应用弹性梁理论、关键层理论推导了覆岩中关键层位置的判别公式,克服了原有判别公式在工程应用中的误差和不便。采用数值模拟方法,研究了覆岩的动态移动规律、应力场分布的动态变化规律、离层产生过程及扩展规律、条带煤柱的失稳过程。根据数值模拟结果和前人的研究成果,对离层的产生机理、条件及影响因素,离层位置的判别,条带煤柱的稳定性及判别,条带尺寸的设计方法等进行了研究。基于采动对离层层位的影响程度,将开始闭合前的离层划分为三种状态:非充分采动离层、充分采动离层和超充分采动离层,并揭示了离层空间、地表沉陷盆地和采区空间三者之间的辩证关系,对指导离层注浆控制覆岩运动具有重要意义。将采场覆岩结构简化为组合板结构,将各层岩层简化为承受均布荷载的四边简支的矩形岩板,应用弹性薄板理论推导了覆岩岩板荷载的计算公式以及覆岩离层特征量(空间体积、裂隙宽度、断面面积)的计算公式,对计算注浆量和评价注浆效果具有重要意义。提出了离层注浆减沉的动态模型,对减沉机理有了新的认识,认为离层注浆减小了剩余离层空间,降低了地表潜在沉陷幅度。依据岩层移动规律、覆岩离层动态演化规律以及部分开采与充填开采的机理、特点,提出了控制地表沉陷的新方法——条带开采条件下的覆岩离层注浆减沉技术。更多还原

【Abstract】 This thesis is supported by the key science and technology planning project of Hunan province: studying on the green and safe mining technology system in south collieries. On the basis of strip mining and the technology of reducing subsidence by injecting grouts into separate strata, the technology system which couples injecting grouts into separate strata in the overburden and strip mining to improve recovery ratio and the reducing subsidence effect is studied by methods of theory analysis, numerical simulation and engineering examples.Based on the structural characteristic of coal-bearing sequences and the movement characteristic roof overburden, the whole overburden structure is regarded as a composite medium beam with two fixed ends. Considerating differences of physical and mechanical properties among rock strata, the discriminant of key strata in the overburden is educed with elastic beam theory and key strata theory. The discriminant conquers the errors and inconvenience of the original discriminant.The dynamic movement law of overlying strata, the dynamic change laws of stress fileds distribution, the generation process and expanding rule of separated strata, and the instability process of strip pillar are studied with numerical simulation. The production mechanism and conditions of separated strata, the influence factors of separated stratum, the calculation of separated stratum position, the stability of strip pillar and its discriminance and the designing methods of strip sizes are also studied according to the results of numerical simulation and the previous research achievements. Based on the impact of mining on separated stratum, separated stratum before beginning to colse is described as the separated stratum uder non-full extraction, the separated stratum under full extraction and the separated stratum under superfull extraction. Dialectical relationships among separated strata, surface subsidence basin and vacant area are disclosed, which plays an important role in injecting grouts into separated strata to control strata movement.The overburden is abbreviated as a composite slab structure, and each rock stratum is regarded as a rectangular slab with four simply supported edges under homogeneous load. The calculation formulas of the load of rock slab and characteristic values of separated strata are educed by using the elastic slab theory, which has much significance in calculating grouting quantity and estimating grouting effect.The dynamic model of injecting grouts into separated strata to reduce subsidence is proposed, and at the same time, a new consideration on reducing subsidence mechanism is obtained. It is considered that injecting grouts into separated strata reduces partial space of separate strata and latent subsidence range.A new method of controlling surface subsidence, i.e. the technology of reducing surface subsidence by injecting grouts into separated strata in overburden under strip mining is proposed according to the respective mechanism and propertities of partial mining method and mining method with backfill.更多还原