高阶段全尾砂胶结充填体强度特性及充填体配比设计研究

发布时间：2019-01-26 15:06

【摘要】：李楼铁矿是国内大型的地下黑色金属矿山之一,采用1OOm高阶段空场嗣后充填采矿法,分矿房矿柱两步骤回采。由于高阶段、高分段而形成的大结构采场,单个采场空区体积达10～16万m3,在高阶段两步骤回采过程中,一步回采与二步回采的时间衔接、充填体配比及其强度性能、充填体强度在采场中的空间分布规律等方面严重制约采场的安全性和经济性。因此,本文以李楼铁矿为项目依托,通过现场工程地质调查、室内力学实验、理论分析、数值模拟、井下原位强度检测和电镜扫描等多种方法研究高阶段胶结充填体的强度特性及充填配比。主要内容如下:(1)通过工程地质调查和室内力学试验,获取了矿区岩体优势结构面的产状与矿岩力学参数,经过对矿岩的力学参数分析,得到了相关岩体的力学参数,为后续的数值模拟计算和分析奠定了基础。现场调查发现二步回采矿柱时,充填体破坏垮落严重,且破坏部位分布不均匀,突显了充填体料浆配比、强度性能、强度的空间分布及二步回采时间等对二步回采安全性有重要的影响。(2)通过全尾砂材料性能试验研究,建立了全尾砂胶结充填体固化强度与养护龄期之间的数学表达式。在高阶段嗣后充填法中,引入表征胶结充填体的变形比能与矿柱回采释放比能关系的能量匹配系数,获得了该系数与矿石的弹性模量、垂直应力与充填体固结强度的关系,揭示了胶结充填体固化时间与矿柱能量的内在联系,定量分析了二步骤回采矿柱的合理时间。(3)通过分析胶结充填体与围岩的力学接触状态,推导了胶结充填体强度极限侧压状态下的三维力学模型,揭示了充填体应力拱效应的分布规律。采用FLAC两步骤数值模拟,分析了不同配比参数下胶结充填体应力场、位移场和塑性破坏区。综合矿山充填工程布置、三维力学模型以及两步骤数值模拟回采,提出了高阶段采场充填配比设计方案。(4)基于李楼铁矿充填体强度检测和微观电镜扫描实验,对井下原位强度与地表试件进行差异化分析,获得了高阶段采场充填体强度呈“驼峰”分布规律,从微观孔隙结构发育特征揭示了自重压力与采场排水布置对高阶段胶结充填体固化强度的作用机理。在采场充填配比优化区内,实现安全开采的同时,降低了充填成本,提高了经济效益。
[Abstract]:Lilou Iron Mine is one of the large underground ferrous metal mines in China. The method of 1OOm high stage open field subsequent filling mining is adopted, which is divided into two steps of quarry pillar mining. Because of the large structure stope formed by high stage and high section, the volume of single stope goaf reaches 10 ~ 160000 m3. In the high stage two-step mining process, the time connection between one-step extraction and two-step mining, the ratio of backfill and its strength performance are discussed. The safety and economy of stope are seriously restricted by the spatial distribution of backfill strength in stope. Therefore, based on the project of Li Lou Iron Mine, through field engineering geological investigation, laboratory mechanical experiments, theoretical analysis, numerical simulation, In situ strength testing and scanning electron microscopy are used to study the strength characteristics and filling ratio of cemented backfill in high stage. The main contents are as follows: (1) through engineering geological investigation and laboratory mechanical test, the occurrence and mechanical parameters of dominant structure plane of rock mass in mining area are obtained. Through the analysis of mechanical parameters of ore rock, the mechanical parameters of related rock mass are obtained. It lays a foundation for subsequent numerical simulation and analysis. The field investigation found that when the two-step mining pillar was returned, the failure of the backfill was serious, and the distribution of the damaged part was not even, which highlighted the mixture ratio and strength performance of the filling body. The spatial distribution of strength and the time of two-step mining have important effects on the safety of two-step mining. (2) the mathematical expression between the curing strength and curing age of the cemented filling is established through the experimental study of the properties of the whole tailings. In the high stage subsequent filling method, the energy matching coefficient is introduced to characterize the relationship between the deformation specific energy of cemented filling body and the specific energy ratio of pillar recovery and release, and the relationship between the coefficient and the elastic modulus of ore, vertical stress and consolidation strength of filling body is obtained. The relationship between solidification time of cemented filling body and pillar energy is revealed, and the reasonable time of two-step return mining pillar is quantitatively analyzed. (3) the mechanical contact state between cemented filling body and surrounding rock is analyzed. The 3D mechanical model of cemented filling under ultimate lateral pressure is derived, and the distribution of stress arch effect is revealed. Using FLAC two-step numerical simulation, the stress field, displacement field and plastic failure zone of cemented filling body under different proportioning parameters are analyzed. According to the layout of mine filling engineering, three-dimensional mechanical model and two-step numerical simulation, the design scheme of filling ratio in high stage stope is put forward. (4) based on the strength test of the filling body of Lilou Iron Mine and the microscopic electron microscope scanning experiment, The difference analysis between underground in-situ strength and surface specimen is carried out, and the distribution law of the strength of filling body in high stage stope is shown as "hump". The mechanism of gravity pressure and stope drainage arrangement on solidification strength of cemented backfill at high stage was revealed from the microcosmic pore structure development characteristics. In the optimized area of stope filling ratio, the safe mining is realized, the filling cost is reduced, and the economic benefit is improved.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD853.343;TD861.1

【参考文献】