【摘要】：為尋求巖石臨界破壞判據(jù)和前兆特征,在粗砂巖單軸壓縮聲發(fā)射(AE)試驗的基礎(chǔ)上,研究了巖石破壞過程中AE信號頻段占比隨應(yīng)力變化特征,重點分析高、低兩個特征頻段占比隨應(yīng)力變化規(guī)律,同時對兩個特征頻段中不同應(yīng)力水平下AE幅值關(guān)聯(lián)維數(shù)進(jìn)行計算與分析,并建立了基于頻段占比與應(yīng)力間關(guān)系的多頻段AE信號主頻識別判據(jù)模型。研究表明:AE信號頻段占比的分布特征能較好地詮釋巖石破壞所經(jīng)歷的主要過程;巖石破壞過程中,較低頻段AE信號(31.25~46.875 k Hz)占比先減小后增大,較高頻段AE信號(140.625~156.25 k Hz)占比先增大后減小。在臨界破壞狀態(tài)下,高、低兩個特征頻段占比分別出現(xiàn)最大值和最小值,且二者中AE幅值關(guān)聯(lián)維數(shù)都下降到最低。通過對特征頻段占比與應(yīng)力之間的耦合分析,利用特征頻段占比、AE幅值關(guān)聯(lián)維數(shù)的變化可更準(zhǔn)確地對巖石臨界破壞前兆進(jìn)行判別和預(yù)測。
[Abstract]:In order to find out the critical failure criterion and precursor characteristics of rock, on the basis of uniaxial compression acoustic emission (AE) test of coarse sandstone, the variation of frequency ratio of AE signal with stress during rock failure is studied, with emphasis on the analysis of high frequency. At the same time, the correlation dimension of AE amplitude under different stress levels in the two characteristic bands is calculated and analyzed. The main frequency identification criterion model of multi-frequency AE signal is established based on the relationship between frequency band duty cycle and stress. The results show that the distribution characteristics of the proportion in the frequency band of the 1: AE signal can better explain the main process of rock failure, and during the rock failure, the AE signal of the lower frequency band (31.25% 46.875 k Hz) decreases first and then increases. The AE signal (140.625 k Hz) / 156.25 k Hz) in the higher frequency band firstly increased and then decreased. In the critical failure state, the maximum and the minimum ratio of the high and low characteristic frequency bands appear respectively, and the correlation dimension of the AE amplitude decreases to the lowest. By analyzing the coupling between the ratio of the characteristic frequency band and the stress, the variation of the correlation dimension of AE amplitude in the characteristic frequency band can be used to judge and predict the rock critical failure precursor more accurately.
【作者單位】： 北京科技大學(xué)土木與資源工程學(xué)院;內(nèi)蒙古伊泰廣聯(lián)煤化有限責(zé)任公司;中冶建筑研究總院有限公司;
【基金】：國家重點研發(fā)計劃項目(2016YFC0600801) 國家自然科學(xué)基金重點項目(51534002);國家自然科學(xué)基金項目(51174015)
【分類號】：TU45

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