冲击性岩石应力状态与声发射信号频率特征相关性研究

发布时间：2018-05-21 02:06

本文选题：岩石力学 + 冲击倾向性　；参考：《岩石力学与工程学报》2017年06期

【摘要】：岩爆、冲击地压的发生是由岩体本身的物理力学性质与其所处的应力环境等因素综合决定的。声发射(acoustic emission,AE)技术是岩爆、冲击地压等这系列冲击性动力灾害监测预警的一种重要手段。通过分析冲击性岩石在不同受力变形破坏过程中的AE特征,推断岩石内部的性质变化,反演岩石的破坏机制及破坏程度,可进一步为岩爆、冲击地压等冲击性动力灾害源的识别、预警提供重要的技术途径。采用不同频率的AE检测通道,对不同冲击性岩石在不同受力方式下的AE信号频率及基本参数特征进行试验研究,主要研究内容与成果包括:(1)通过对冲击性花岗岩进行单轴压缩、三轴压缩、单轴加卸载、三轴加卸载试验,分析围压对岩石冲击危险性的影响,得到岩石损伤能量释放率与损伤变量之间的关系,确定冲击性花岗岩具备发生冲击危险的最低轴向应力水平。(2)基于单轴加卸载扰动AE试验,研究了冲击性粉砂岩AE响应比值、弹性模量响应比值及变形响应比值随轴向相对应力水平变化规律,提出了在实际应用中,可综合利用多种因素响应比值变化规律进行联合预判来提高岩体失稳破坏预测的准确性。(3)通过对冲击性花岗岩在不同围压下循环加卸载AE试验,得到岩石加卸载损伤破坏过程中高、低2种频率的AE通道中AE累计振铃计数、应力与时间的关系。基于此,研究AE不可逆性特征。同时,运用快速傅里叶变换FFT逆变换对Kaiser点的AE信号进行消躁,并采用FFT分析消躁后信号的频谱特征,得到冲击性花岗岩发生主破裂前Kaiser点的主频特征及变化规律,为进一步反演冲击性岩石的损伤破坏机制及破坏程度提供依据。(4)在冲击性花岗岩不同围压下循环加卸载AE试验的基础上,运用小波包频段分解法和G-P算法对Kaiser点信号及其相邻点的频段能量分布特征与AE能量关联维数进行研究,得到Kaiser点特征频段变化规律及Kaiser点AE关联维数均小于其相邻点的结论,为进一步揭示冲击性岩石的损伤破坏机制提供参考依据。(5)研究不同冲击倾向性岩石在单轴压缩和三轴压缩下的AE频率和基本参数特征,得到较强冲击性岩石、较弱冲击性岩石和非冲击性岩石在不同受力及变形破坏阶段的AE频率、优势频率、振铃计数、能量、撞击数等相关参数变化特征及规律,进一步为岩爆、冲击地压等冲击性动力灾害源的AE技术识别、预警提供基础依据。(6)建立了基于AE信号频段与岩石力学参数间关系的多频段AE信号频率识别模式,在此基础上,研究了冲击性花岗岩在单轴和三轴压缩下频率分布特征,得到冲击性花岗岩在单轴和三轴压缩下破坏失稳及临界破坏状态的频率组合识别模式。
[Abstract]:Rock burst, the occurrence of rock burst is determined by the physical and mechanical properties of rock mass and its stress environment. Acoustic emission (acoustic emission, AE) technology is an important means of monitoring and warning of rock burst, rock burst and so on. The characteristics of AE in the process can be used to deduce the changes in the nature of the rock, to reverse the failure mechanism and damage degree of rock, and to further provide an important technical approach for the identification of rock burst, rock burst and other impact dynamic disaster sources. The AE detection channel with different frequencies is used for the AE signals of different impact rocks under different stress modes. The main research contents and results are as follows: (1) through uniaxial compression, three axis compression, uniaxial loading and unloading, and three axis loading and unloading tests, the influence of confining pressure on rock impact risk is analyzed, the relationship between rock damage energy release rate and damage variable is obtained, and the impact is determined. The striking granite has the lowest axial stress level of the impact risk. (2) based on the uniaxial loading and unloading disturbance AE test, the AE response ratio, the response ratio of the elastic modulus and the ratio of the deformation response to the axial relative stress level are studied, and the response ratio of various factors can be used in the practical application. The variation law of value is combined to improve the accuracy of rock failure prediction. (3) through the cyclic loading and unloading of the impact granite under different confining pressure and AE test, the cumulative ringing count of AE and the relationship between stress and time in the AE channel of rock loading and unloading damage are obtained. Based on this, the irreversibility of AE is studied. At the same time, using the fast Fourier transform FFT inversion to eliminate the AE signal of the Kaiser point, and using the FFT analysis of the spectrum characteristics of the impulsive signal, the main frequency characteristics and change rules of the Kaiser point before the main rupture of the impact granite are obtained, so as to provide the further inversion of the damage mechanism and damage degree of the impact rock. (4) on the basis of the cyclic loading and unloading AE test under different confining pressure of the impacting granites, the wavelet packet frequency section decomposition method and the G-P algorithm are used to study the frequency energy distribution characteristics of the Kaiser point signal and its adjacent points and the correlation dimension of the AE energy, and the variation of the frequency band of the Kaiser point and the Kaiser point AE correlation dimension are less than that of it. The conclusion of adjacent points provides a reference for further revealing the damage and damage mechanism of impact rocks. (5) study the characteristics of AE frequency and basic parameters of different impact tendencies rock under uniaxial compression and three axis compression, and get strong impact rock, weak impact rock and non impact rock in different stress and deformation damage order AE frequency, dominant frequency, ringing count, energy, impact number and other related parameters change characteristics and rules, and further provide basic basis for AE technology identification and early warning for rock burst, rock burst and other impact dynamic disaster sources. (6) a multi band AE signal frequency identification model based on the relationship between AE signal frequency and rock mechanics parameters is established. On this basis, the frequency distribution characteristics of impacting Granites under uniaxial and three axial compression are studied, and the frequency combination pattern of failure and critical failure state of impacting Granites under uniaxial and three axial compression is obtained.
【作者单位】：江西理工大学资源与环境工程学院;
【基金】：国家重点研发计划(2016YFC0600801) 国家自然科学基金资助项目(51174015,51364012)~~
【分类号】：TU45

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