空场嗣后充填连续开采胶结体强度模型及其应用

发布时间：2017-12-26 19:39

本文关键词：空场嗣后充填连续开采胶结体强度模型及其应用　出处：《昆明理工大学》2017年博士论文　论文类型：学位论文

【摘要】：随着绿色开采技术的发展,以及国家固体非能源矿产"三率"评价标准的推行,充填采矿法必将得到广泛的应用。盘区机械化连续开采、安全高效、低成本及低贫损是充填采矿技术的核心研究主题。两步骤的空场嗣后充填法是开采矿石围岩中等稳固、中厚及以上矿体的主体采矿方法。该法分两步骤回采,矿柱胶结充填,矿房非胶结充填。为最大限度提高矿石回收率,该法已发展为无矿柱连续开采模式。稳定的胶结充填体形成的支撑框架是回采矿房的安全保障。如何科学合理地确定胶结体强度是空场嗣后充填法的关键,也关系到降低充填成本的现实要求。当前,缺乏对该类胶结充填体所需强度的系统研究,其强度设计大多采用经验类比法等,往往造成充填体强度与工程实际要求不符。有的矿山因充填体强度不足发生充填体崩塌,有的矿山则因充填体强度过高而造成充填成本居高不下影响效益,可见科学合理的胶结体强度,直接影响到矿体安全、高效开采及矿石开采率指标。因此,有必要根据两步骤空场嗣后充填法的工艺特点,基于充填体的受力状态,建立胶结充填体的强度模型,这对深化充填采矿理论研究和指导矿山生产实践都具有重要意义。本文通过分析两步骤空场嗣后充填法开采步骤的变化对胶结充填体受力状态的影响,结合充填体作用机理的研究现状,认为胶结充填体的力学作用主要表现为改善顶板岩体受力状态支撑顶板破碎岩体、为侧帮卸载岩块的滑移趋势提供侧限压力、抵抗采场闭合和限制尾砂流动,基于胶结充填体为"自立性人工矿柱"特点开展建模及研究工作。研究方法及成果如下:(1)通过对大红山铜矿空场顶板跨落实测结果的统计分析,建立了平衡拱高度与采场结构尺寸、围岩稳定性的关系。将采场顶板平衡拱与胶结充填体接触部分对应拱顶石重力视为岩层作用于胶结充填体顶部的压力,确定了胶结充填体顶部压力的计算方法。(2)以滑移角确定采场围岩片帮范围,指出侧帮围岩滑移面上抗滑阻力与胶结充填体作用力共同保持具有滑移趋势的三维楔形体稳定,采用楔体滑动理论建立了采场侧帮滑移块体的极限平衡状态方程,并推导了采场侧帮对胶结体的压力。(3)根据尾砂三联杆高压固结实验结果,分析得出尾砂密度随压力的变化关系满足幂函数特征。通过分析自重条件下采场内任意高度尾砂微元体的平衡条件,建立了大体积尾砂充填体自压密规律(即尾砂密度随高度的变化关系)。采用Fluent模拟采场内尾砂密度的分布状态,结果表明,相同高度条件下数值模拟结果与模型计算结果密度最大差值为0.062t/m3,最小差值为0.001t/m3,平均密度相差0.011t/m3,结果高度吻合。(4)采用莫尔-库仑准则及楔体滑动理论,分析胶结体和尾砂充填体接触面上尾砂单元体极限应力状态以及尾砂三维楔形体的极限平衡状态,结合尾砂自压密规律,分别建立了尾砂充填体对胶结体侧压力的计算方法,两种分析方法虽然不同,但却能推导出相同的结果。(5)综合以上研究内容,建立了两步骤空场嗣后胶结充填体最不利状态下(一侧临空、一侧受非胶结尾砂侧压力条件下)的强度模型,包括内聚力计算模型、抗压强度计算模型和抗剪强度计算模型。模型充分考虑了胶结充填体结构尺寸、顶板松散岩体重力、围岩作用力、胶结充填体与围岩之间的接触条件以及尾砂充填体对胶结体侧压力等因素,更符合采场实际情况。(6)采用FLAC 3D建立了大红山铜矿385中段48-54线区段的数值模型,根据空场嗣后胶结体强度模型计算结果(强度随高度的变化关系),对区段内胶结矿柱分层赋值强度参数。根据试块强度实验和应力应变实验结果,选择胶结矿柱分层变形参数。选用Model morh(本构模型为莫尔-库仑模型)进行计算。结果表明,385中段48-54线区段内胶结矿柱按设计的强度参数及分层充填方式条件下,在区段回采过程中均能保持稳定。(7)本文研究成果应用于大红山铜矿48-54线区段大盘区空场嗣后充填连续开采的生产实践。经矿山统计,共采出矿石2238919t,平均品位0.45%,贫化率10.03%,回收率87.5%,盘区生产能力达2487t/d。区段内胶结矿柱服务至整个区段回采结束未发生大规模垮塌。工业应用证明,依据本文建立的胶结充填体强度模型设计的充填体强度及配合比符合大红山铜矿生产实践要求。论文研究成果对深化充填采矿理论研究具有重要意义,对相似矿山具有较高的应用和推广价值。
[Abstract]:With the development of green mining technology and the implementation of the "three rate" evaluation standard of national solid non energy mineral resources, the filling mining method will be widely used. Continuous mechanized mining, safety and efficiency, low cost and low poverty are the key research topics of filling mining technology. The two step method of open stope filling is the mining of ore rock solid, medium thick and ore body mining method. The method is divided into two steps, the pillar of cemented filling stope non cemented filling. In order to maximize the recovery of ore, the method has been developed into a continuous mining mode without pillar. The formation of cemented backfill support frame stability is the security of the mining stope. How to scientifically and reasonably determine the cementation strength is the key of open stope filling method, but also to reduce the cost of filling the practical requirements. At present, there is no systematic research on the strength required for such cemented filling body. Most of the strength design is based on experience analogy method, which often results in inconsistent strength of filling body and engineering practice. Some mines cause filling body collapse due to insufficient strength of filling body. Some mines result in high cost of filling due to high strength of filling body, which results in high efficiency. Therefore, scientific and reasonable cementation strength directly affects the safety, efficient mining and ore productivity index. Therefore, it is necessary according to the technical characteristics of the two steps of open stope filling method, the stress state of backfill based on strength, model of filling, which is of great significance to deepen the theoretical research and production practice of filling mining guide. The change of two steps of open stope backfill mining step effect analysis on the stresses of filling, according to the status quo of filling body mechanism, that the mechanical effect of filling is mainly to improve the stress state of the rock in the roof supporting roof broken rock, providing resistance to stope closure and limit tailings flow pressure the side limit of side slip tendency of rock block, filling based on the development of the work of modeling and Research on independence of artificial pillar "characteristics. Research methods and results are as follows: (1) through the statistics of Dahongshan Copper Mine Stope Roof Caving results analysis, established the relationship between balanced arch height and size of the stope structure, surrounding rock stability. The calculation method of the top pressure of cemented backfill is determined according to the pressure of the top crown balance arch and the cemented filling part, which corresponds to the stress of the top crown acting on the top of the cemented filling body. (2) to determine the slip angle of stope surrounding rock spalling scope, pointed out that the side slip force of anti sliding rock body resistance and cemented together maintain three-dimensional wedge stability with sliding trend, the wedge theory establishes the state equation of limit equilibrium of stope side sliding block, and deduced stope side of the cement body pressure. (3) according to the experimental results of the high pressure consolidation of the tailings triplex, it is found that the relation between the density of the tailings and the pressure is satisfied with the power function. By analyzing the equilibrium condition of the tailings micro element with arbitrary height under the condition of self weight, the self compaction law of tailings filling body is established, that is, the relationship between tailings density and height. Fluent is used to simulate the distribution state of tailings density in the stope. The results show that under the same height condition, the maximum difference between numerical simulation results and model calculation results is 0.062t/m3, the minimum difference is 0.001t/m3, and the average density difference is 0.011t/m3, the result is highly consistent. (4) by using the Mohr Coulomb criterion and wedge sliding contact theory, analysis of cemented tailings filling body and on the surface of tailings unit limit stress state and tailings 3D wedge limit equilibrium state, combined with the self compaction of tailings, pressure calculating method of cemented tailing backfill body side were established, two methods are different, but it can derive the same results. (5) based on the above research, the most unfavorable two steps of open stope filling condition is established (one side, one side by airport uncemented sand under lateral pressure) strength of the model, including the calculation model and calculation model of shear strength and compressive strength of the cohesive force calculation model. The model takes full account of the structural size of cemented filling body, the gravity of the loose rock mass, the force acting on the surrounding rock, the contact condition between the cemented backfill body and the surrounding rock, and the side pressure of tailings filling body on the cementation body, which is more consistent with the actual situation of the stope. (6) to establish a numerical model of Dahongshan Copper Mine 385 middle line sections with FLAC 48-54 3D, according to the results of open stope cementation strength model (intensity variation with height, relation) parameters of the backfill pillar layered section strength assignment. The stratified deformation parameters of the cemented pillar are selected on the basis of the test and stress strain test results of the test block. Model morh (constitutive model for Mohr Coulomb model) is used to calculate. The results show that the cementation pillar in the 385 middle 48-54 line section is stable under the condition of design strength parameters and stratified filling mode. (7) the results of this study used in the production practice of Dahongshan Copper 48-54 line segment market area of open stope filling of continuous mining. Through the mine statistics, the ore 2238919t was collected, the average grade was 0.45%, the dilution rate was 10.03%, the recovery rate was 87.5%, and the production capacity of the disk area was up to 2487t/d. The cemented pillar service in the section to the end of the whole section did not collapse in a large scale. It is proved by industrial application that the strength and mix ratio of the filling body designed according to the strength model of cemented filling body established in this paper meet the requirements of the production practice of the great Hongshan copper mine. The research results of this paper are of great significance for deepening the research on the theory of filling mining, and have high application and popularization value for similar mines.
【学位授予单位】：昆明理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD853.34;TD862.1

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