【作者】 杨清波；

【导师】 戴兴国；

【作者基本信息】 中南大学 ， 采矿工程， 2011， 硕士

【摘要】 长期以来,在岩体稳定性问题的研究中多是依靠经验、半经验的方法分析,一些潜在的不安全因素难以得到揭示。随着工程规模和复杂性的日益增大,这种依靠经验的方法越来越不能适应发展的工程实际需要,难以有效解决岩体工程中的稳定性问题。在岩土和地下工程中,经常遇到的岩石力学问题是需要确定开挖前后的应力和位移及其在开挖过程中的变化,以便为设计和施工提供可靠的定量依据。然而已有的理论往往只能解决圆形或椭圆形等简单孔周应力场和位移场,对于几何形状复杂的孔洞如采场问题只能用数值模拟方法来近似求解。随着计算分析软件的发展数值模拟方法有了显著的进步,已成为岩石力学研究和工程计算的重要手段。冬瓜山铜矿第三步骤回采隔离矿柱的时候,由于经过前面大规模的第一步骤矿房回采和第二步骤矿柱回采,采矿技术条件已经发生了更本性的变化。首先,隔离矿柱周围的介质由强度很好的矿岩体基本变成了强度较低的尾胶充填体或基本没有强度的尾砂充填体；其次,由于受地压转移效应的影响,隔离矿柱内的应力会明显增大,矿岩体次生节理裂隙可能大量发育(矿岩体原生节理均不发育,平均1条/m)；总之,到第三步骤回采隔离矿柱的时候,采矿技术条件比第一步骤回采矿房和第二步骤回采矿柱的时候严重恶化。本文针对冬瓜山铜矿盘区隔离矿柱回采时围岩力学性质的复杂性,主要研究内容为受大规模采动影响后隔离矿柱开采技术条件的研究,以及隔离矿柱采场合理结构尺寸参数的数值模拟研究。具体内容包括以下几点：(1)对深井开采岩体破坏机理进行研究,明确岩体破坏的基本方式,然后对岩体破坏判据进行讨论和分析。最后,通过对岩体稳定性的分析,总结出综合考虑极限应力和应变条件,来对地下工程岩体稳定性进行综合评判。(2)分析冬瓜山铜矿暂留隔离矿柱阶段空场嗣后充填采矿方法的技术与经济条件,分析隔离矿柱回采技术与工艺的复杂性。(3)通过分析冬瓜山铜矿隔离矿柱回采的各项技术条件,选取影响隔离矿柱回采稳定性的6项因素,按照正交试验的原理,安排8种不同的数值模拟试验方案。(4)应用FLAC3D软件数值模拟,分析隔离矿柱回采前的开采技术条件,完成对8种方案的模拟试验,并比较各方案条件下的最大应力应变数值和规律,进而分析围岩稳定性状态。然后通过正交分析,得出6项因素对隔离矿柱回采稳定性影响的权重。(5)根据数值模拟结果正交分析得出的各因素影响权重,结合冬瓜山铜矿开采的技术与经济条件,建议一个隔离矿柱回采结构参数较优的方案。更多还原

【Abstract】 Over the years, it mainly relies on the method of multiple, semi-empirical experience to analyze the rock stability problems, however, some potential insecure elements are difficult to be revealed. This method can not meet the needs of the actual engineering with the increasing project size and complexity, it can not effectively solve the stability problems in rock engineering. The need to determine the stress and strain around the excavation and changes in the excavation process is often encountered in rock mechanics problems in geotechnical and underground engineering, it can provide reliable quantitative basis for the design and construction. However, the existed theories can only solve such a simple round or oval holes on stress and strain fields, the complex geometry of the holes, such as mining field problems, can only be approximated by numerical simulation solution. With the development of analysis software, numerical simulation method has made substantial progress, and has become an important means in rock mechanics research and engineering calculations.Before the excavation of the third step, the barrier pillar in Dongguashan Copper Mine, we have excavated a large scale of the first steps and the second steps, so the mining technology conditions have essentially changed. First, the medium around the barrier pillar are turned into tailings backfill, which have low strength or little plastic strength. Secondly, due to the affect of the pressure transfer, the stress within the barrier pillar have been significantly increased, the mine fractured rock mass may be a lot of secondary development. In short, when excavating the third steps, the technical conditions of mining is more seriously deteriorated than it in the first steps and the second steps.The main research content of this paper are the mining technical conditions of the barrier pillar after the large-scale mining effect, and the numerical simulation about the reasonable structure size of the barrier pillar. Contents include the following:(1) Ascertaining the basic form of mass failure after the research of rock failure mechanism in deep mine. Then discussing and analyzing the rock mass failure. (2) Analyzing the technical and economic conditions of the stay barrier pillar level room subsequent filling mining method, analyzing the technical complexity of the excavation of barrier pillar.(3) Selecting six factors of affecting the barrier pillar stability, in accordance with the principle of orthogonal design, arranging 8 kinds of numerical simulation test program.(4) Analyzing the barrier pillar’s mining technical condition by applying FLAC3D numerical simulation software. Complete the 8 kinds of numerical simulation test program, and compare the maximum stress values and discipline under the various programs, and then analyzes the stability of surrounding rock state. At last, obtain the weight of the six factors on the barrier pillar’s stability by orthogonal analysis.(5) According to the weight of 6 factors obtained in the orthogonal numerical simulation, and combined with the technical and economic conditions in Dongguashan Copper Mine, propose an optimum scheme of the structure parameters in the excavation of barrier pillar.更多还原