深部岩体超低摩擦效应的FLAC-3D数值模拟研究

发布时间：2018-12-26 11:23

【摘要】：随着开采深度增加,岩体动力学行为表现出新特征和新现象,深部岩体超低摩擦效应产生机理是其中关键科学问题之一。由于超低摩擦效应,岩体平衡关系和约束条件被破坏,极易发生平动和转动,从而诱发岩爆、冲击地压等动力灾害,对矿山安全开采构成巨大威胁。因此,研究深部岩体超低摩擦效应对矿山安全开采及煤岩动力灾害预测与防治具有重要价值和实际应用意义。本文以花岗岩块体模型为研究对象,采用FLAC-3D数值软件对两种加载条件,即垂直冲击和水平静力共同作用、垂直冲击和水平冲击共同作用下,深部岩体超低摩擦效应进行了数值模拟,得到了模型中工作块体水平位移、法向力演变规律及块体模型垂直方向及水平方向应力的分布特征。研究表明：花岗岩块体模型在两种加载条件下,随着冲击载荷幅值增大,工作块体法向力幅值变化范围和水平残余位移均逐渐增大,从而导致了超低摩擦效应发生,并且越来越明显；随着冲击载荷频率增大,工作块体接触面法向力衰减速度增加,水平残余位移减小,超低摩擦效应不断减弱；随着开采深度增加,工作块体水平残余位移及法向力均逐渐增加,超低摩擦效应愈加明显。垂直冲击和水平冲击共同作用于花岗岩块体模型时,水平冲击载荷先于或后于垂直冲击载荷施加,法向力幅值的变化范围均增大,超低摩擦效应更趋显著。水平冲击载荷引起的水平残余位移远大于垂直冲击载荷引起的水平残余位移,因此,在接触面平行方向上的水平冲击是深部岩体超低摩擦效应主要影响因素。
[Abstract]:With the increase of mining depth, the dynamic behavior of rock mass shows new characteristics and new phenomena. The mechanism of ultra-low friction effect in deep rock mass is one of the key scientific problems. Because of the ultra-low friction effect, the equilibrium relationship and constraint conditions of rock mass are destroyed, and it is easy to occur translation and rotation, thus inducing dynamic disasters such as rockburst and ground pressure, which pose a great threat to the safe mining of mines. Therefore, it is of great value and practical significance to study the ultra-low friction effect of deep rock mass for safe mining, prediction and prevention of coal-rock dynamic disasters. In this paper, the granite block model is studied, and two loading conditions, vertical impact and horizontal static force, vertical impact and horizontal impact, are analyzed by using FLAC-3D software. The ultra-low friction effect of deep rock mass is numerically simulated, and the horizontal displacement and normal force evolution of the working block in the model and the distribution characteristics of the vertical and horizontal stress in the block model are obtained. The results show that under two loading conditions, the range of normal force amplitude and the horizontal residual displacement of the working block gradually increase with the increase of impact load amplitude, which leads to the occurrence of ultra-low friction effect. And more obvious; With the increase of the impact load frequency, the normal force attenuation velocity of the working block contact surface increases, the horizontal residual displacement decreases, and the ultra-low friction effect weakens. With the increase of mining depth, the horizontal residual displacement and normal force of the working block increase gradually, and the effect of ultra-low friction becomes more obvious. When the vertical impact and horizontal impact act on the granite block model, the amplitude of normal force increases, and the effect of ultra-low friction becomes more obvious when the horizontal impact load is applied before or after the vertical impact load. The horizontal residual displacement caused by the horizontal impact load is much larger than the horizontal residual displacement caused by the vertical impact load. Therefore, the horizontal impact in the parallel direction of the contact plane is the main factor affecting the ultra-low friction effect of the deep rock mass.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD32

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