基于声发射参量识别不同深度灰岩岩爆倾向研究

发布时间：2018-05-21 15:17

本文选题：单轴 + 岩爆倾向性　；参考：《江西理工大学》2017年硕士论文

【摘要】：埋藏于深部和中深部金属矿山由于地应力的不断增大诱发岩爆可能性越来越大。由深部开采高应力引起的开采技术问题越来越多,根据矿床开采技术条件和矿体赋存特征。避免岩爆带来的危害,选择经济合理的防护措施以实现矿山安全高效开采,保证矿山可持续生产,是目前越来越多金属矿山迫切需要解决的重大技术问题。深部岩体在地壳运动作用下应变能大量聚集,形成很大的初始应力。深部回采使得聚集的应变能突然释放形成岩爆,岩爆的发生一方面与初始应力场有关,另一方面与岩石承载过程中变形及储能特性有很大的关联。岩石破坏过程伴随了弹性波的释放,而声发射监测技术能捕捉岩石加载过程产生的瞬态弹性波,所以利用声发射检测结果作为岩石材料破裂判据在岩石力学研究领域一直都是研究重点。声发射表征岩石破坏方面形成众多有益结论,但真正将声发射测试用于岩爆的判别尚不多见。本次课题采用弹性能量指数作为岩石岩爆倾向性判据。进行深部回采不同深度灰岩试样的岩爆倾向性实验,得到了不同深度灰岩试样的加卸载过程应力-应变曲线。在实验过程中进行声发射测试,分析加卸载全过程声发射累计能量随时间的变化规律,得到不同岩爆倾向性试样声发射累计能量变化特征,通过实验数据分析揭示岩爆倾向灰岩声发射响应特征。通过分析试验过程声发射累计能量变化率,定义了累计能量反应比E_k等于加卸载过程声发射累计能量变化率与加卸载转折点声发射累计能量变化率的比值。结果表明:(1)随着深度的增加,岩石单轴抗压强度有逐步增大的趋势,这为岩石的岩爆发生提供了有利条件,进而印证了随深度增加灰岩岩爆发生的可能性越大,从另一方面说明了岩石的岩爆与深度有着密切相关性。(2)加载时,随着赋存深度增加,岩石存储应变能的能力在增强;卸载时,随着深度增加,深度越深灰岩在卸载过程的声发射累积能量增加幅度越小,由此可知不同深度灰岩累积能量的变化率存在明显的区别。(3)随着赋存深度增加,灰岩加卸载滞回环的面积逐步减小,说明灰岩存储应变能的能力逐步增加,这是诱发岩爆的重要因素。岩石的岩爆倾向呈现越来越大的趋势:对不同深度灰岩试样进行岩爆倾向性实验,分析加卸载过程弹性应变能指数W_(et)发现,随深度增加,弹性应变能指数逐渐增大,岩爆倾向趋于明显。(4)通过加卸载过程累计声发射能量进行分析表明,加载和卸载过程中岩爆倾向性不明显的灰岩试样声发射累计能量的增加幅度要远大于具有明显岩爆倾向的灰岩试样,且随着岩爆倾向性增强,声发射累计能量的增加幅度在逐步变小。加卸载转折点处,具有明显岩爆倾向的灰岩声发射累计能量出现突增现象。(5)通过对加卸载全过程声发射累计能量变化率进行分析,定义了声发射累计能量反应比E_k。通过实验发现,当E_k值大于1时,岩石岩爆倾向性不明显;当E_k值小于1时,岩石岩爆倾向性较强,另外,加载和卸载的过程中E_k值越平静,岩爆的倾向性越强。因此,通过实验过程得到的声发射累计能量反应比E_k值可为深部岩石岩爆倾向性判识提供一定的参考依据。
[Abstract]:In the deep and middle and deep metal mines, the possibility of rockburst is more and more likely to be induced by the increasing stress in the mine. More and more mining technologies are caused by the high stress in deep mining. According to the mining technical conditions and ore deposit characteristics, the damage caused by rock burst is avoided, and the economical and reasonable protective measures are selected to realize the mine safety. Fully efficient mining, ensuring the sustainable production of the mine, is an important technical problem which is urgently needed to be solved in more and more metal mines at present. The strain energy of deep rock mass accumulated in the crust movement, forming a large initial stress. Deep mining makes the accumulated strain energy suddenly released to form rock burst, and the occurrence of rock burst in one aspect and the initial stage The stress field is related to the other. The other is related to the deformation and energy storage characteristics during the rock loading process. The rock failure process is accompanied by the release of elastic waves, and the acoustic emission monitoring technology can capture the transient elastic waves produced by the rock loading process, so the acoustic emission test results are used as the rock material fracture criterion in the rock mechanics research. The field has always been the focus of research. Acoustic emission characterizing rock failure has formed many beneficial conclusions, but it is not quite common to discriminate the acoustic emission test for rock burst. This subject uses elastic energy index as the rock burst tendency criterion. The stress strain curve of the loading and unloading process of the same depth limestone samples. During the experiment, the acoustic emission test was carried out to analyze the variation of the cumulative energy of acoustic emission with time, and the variation of the cumulative energy of acoustic emission of different rock burst tendentious specimens was obtained. The acoustic emission response of rock burst inclined limestone was revealed through the experimental data analysis. Characteristics. By analyzing the cumulative energy change rate of acoustic emission in the test process, the ratio of cumulative energy response ratio (E_k) to the cumulative energy change rate of acoustic emission (sonic emission) and unloading process is defined. The results show that: (1) the uniaxial compressive strength of rock increases gradually with the increase of depth. It provides favorable conditions for rock burst occurrence, and then confirms that the greater the possibility of increasing the occurrence of rock burst with depth, on the other hand, it shows the close correlation between rock burst and depth of rock. (2) when loading, the capacity of rock storage strain energy is enhanced with the increase of the depth of occurrence; when unloading, the depth increases with the depth, the more depth. The cumulative energy increase of the deep limestone in the unloading process is smaller, thus it can be seen that there is a distinct difference in the cumulative energy change rate of the limestone at different depths. (3) the area of the hysteresis loop of the limestone adding and unloading gradually decreases with the increase of the depth of the deposit, which indicates that the capacity of the limestone storage strain energy is gradually increased, which is an important factor to induce the rock burst. The rock burst tendency is becoming more and more trend: the rock burst tendency experiment of different depth limestone samples, the analysis of elastic strain energy index W_ (ET) of the loading and unloading process, the elastic strain energy index gradually increases with the depth, and the ROCKBURST TENDENCY tends to be obvious. (4) the analysis of cumulative acoustic emission energy through loading and unloading process shows that the rock burst tendency tends to be obvious. In the process of loading and unloading, the increase of the cumulative energy of acoustic emission is much greater than that of the limestone sample with obvious rock burst tendency, and with the increase of rockburst tendency, the increase of the accumulative energy of acoustic emission is gradually smaller. The cumulative energy increases abrupt. (5) through the analysis of the cumulative energy change rate of the acoustic emission in the whole process of loading and unloading, the cumulative energy response ratio of acoustic emission (E_k.) is defined by the experiment. When the E_k value is greater than 1, the rock and rock burst tendency is not obvious; when the E_k value is less than 1, the rock rock burst tends to be stronger, in addition, loading and unloading process. The more calm the E_k value is, the stronger the tendency of rock burst. Therefore, the cumulative energy response of acoustic emission obtained through the experiment can provide some reference for the rock burst orientation of deep rock.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD313

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