松散介质堆积体滑移破坏声发射预测试验研究

发布时间：2018-04-14 18:26

本文选题：松散介质堆积体 + 模型试验　；参考：《江西理工大学》2017年硕士论文

【摘要】：矿山常见排土场堆放的废石土及选矿厂排放的尾矿都属于松散介质堆积体,这些堆积体失稳滑移将造成严重的安全事故,给国家、社会带来难以估量的损失,因次对排土场和尾矿库进行失稳前兆的预测具有非常重要的价值和意义。目前排土场和尾矿库稳定性的监测主要是对其表面和内部的变形、位移进行监测,无法真实反映其内部松散体颗粒间的错动滑移情况。声发射能反映被监测物体内部的破坏机理,排土场及尾矿库失稳时松散介质间的滑动摩擦将产生声发射,因而将声发射用于监测排土场及尾矿库的稳定性具有其可能性。本文拟以松散介质堆积体之一的排土场为研究对象,通过构建散体边坡模型,进行散体边坡滑移破坏的声发射试验。采用试验研究与理论分析相结合的方法,进行了松散体滑移破坏过程声发射信号特性研究,得到了以下的结论:(1)设计了一套散体边坡模型试验装置,通过构建滑移面使得散体边坡发生滑移破坏,同时在坡顶、坡中及坡底3个位置布置了声发射信号监测点,并借助波导杆传播声发射信号来监测散体边坡的破坏过程。试验结果表明,散体边坡的滑移破坏是循序渐进及能量累计的过程,即大规模破坏前,会出现多次小规模破坏,并且可将边坡面出现大面积范围废石滚动的现象,作为大规模滑移破坏失稳的前兆。(2)结合试验过程现象及破坏规模的大小,将整个散体滑移破坏过程划分为几个阶段,并就试验全过程的声发射信号相关参数进行了分析,结果表明,散体边坡的声发射活动伴随着整个滑移破坏过程,各阶段声发射特征参数的变化可以在一定程度上揭示散体边坡内部状态的演化过程。(3)不同位置的声发射特征参数存在显著差异,其中处于坡底3#测点接收的声发射信号最强,并且结合3个测点分析更能反映散体滑移破坏的情况。同时根据不同位置声发射信号出现的时间先后,能够预判出破坏发生的范围,当所有监测点都有声发射信号并突然加强时,预示有大规模滑移破坏的发生。(4)滑移破坏过程关联维数D和r值的变化与散体内部状态的演化密切相关,其中分形维数D值会在临近滑移阶段的附近出现最大值,并且之后会突然出现突降现象和临近滑移破坏附近r值会出现“断崖式”聚减的现象,都可作为散体边坡失稳破坏的前兆。(5)采用小波包频带能量分析方法,重点分析散体边坡滑移破坏位置处的频带能量分布规律,得到了散体滑移破坏时,声发射主频主要位于15.6 kHz~77.1 kHz,相应的次频主要位于77.1kHz~140.6 kHz。
[Abstract]:The waste rock and tailings discharged from the common dump of mine belong to the accumulation of loose media. The unstable slip of these deposits will cause serious safety accidents and bring incalculable losses to the country and society.It is of great value and significance to predict the instability precursor of dump and tailings.At present, the monitoring of the stability of dump and tailings is mainly to monitor the deformation and displacement of its surface and interior, which can not truly reflect the dislocation and slip between the particles in the loose body.Acoustic emission can reflect the failure mechanism inside the monitored object, and the sliding friction between loose media will produce acoustic emission when the dump and tailings are unstable, so it is possible to use acoustic emission to monitor the stability of dump and tailings reservoir.In this paper, an acoustic emission test of slip failure of a loose mass slope is carried out by constructing a model of a loose mass slope, which is one of the dumping sites of loose media.By combining the experimental study with the theoretical analysis, the acoustic emission signal characteristics of the slip failure process of loose body are studied. The following conclusions are obtained: 1) A set of model test device for the loose slope is designed.The slip surface is constructed to cause the slip failure of the slope. At the same time, the acoustic emission signal monitoring points are arranged at the top, the middle and the bottom of the slope, and the acoustic emission signal is transmitted by the waveguide rod to monitor the failure process of the bulk slope.The test results show that the slip failure of the slope is a gradual process and energy accumulation process, that is, before the large-scale destruction, there will be many small scale failure, and the slope surface can be rolled over a large area of waste rock.As a precursor of large-scale slip failure instability, combined with the phenomenon of experimental process and the size of failure scale, the whole slip failure process is divided into several stages, and the relevant parameters of acoustic emission signal in the whole test process are analyzed.The results show that the AE activity of the bulk slope is accompanied by the whole slip failure process.The variation of acoustic emission characteristic parameters in each stage can reveal to some extent the evolution process of the internal state of a loose slope. (3) there are significant differences in the acoustic emission characteristic parameters at different positions, among which the acoustic emission signal received at the measuring point at the bottom of the slope is the strongest.Combined with the analysis of three measuring points, the slip failure of the bulk can be better reflected.At the same time, according to the time sequence of acoustic emission signals at different locations, the scope of destruction can be pre-determined. When all monitoring points have acoustic emission signals and suddenly strengthen,The variation of correlation dimension D and r value in the process of slip failure is closely related to the evolution of the internal state of the bulk, and the fractal dimension D value will appear the maximum value near the slip stage.The phenomenon of sudden drop and the phenomenon of "precipitous" accumulation and reduction near the value of r near the slip failure will appear suddenly afterwards, which can be used as a precursor to the failure of a loose slope. (5) the method of wavelet packet frequency band energy analysis is used.The distribution of frequency band energy at the slip failure location of the slope is analyzed. The results show that the main frequency of acoustic emission is mainly located at 15.6 kHz~77.1 Hz, and the corresponding secondary frequency is mainly located at 77.1kHz~140.6 kHz.
【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】：TD854.7;TD926.4

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