煤卸荷过程中声发射特征及综合破坏前兆分析

发布时间：2018-06-25 06:56

本文选题：岩石力学 + 煤　；参考：《四川大学学报(工程科学版)》2016年S2期

【摘要】：为探究煤破坏全过程的声发射(acoustic emission,简称AE)特征及破坏前兆信息,利用MTS815岩石力学试验系统和PCI-2型声发射监测系统,对不同初始围压下煤样的卸荷破坏进行声发射试验,得到煤在卸荷过程中AE特征的围压效应及基于声发射的多参数综合破坏前兆信息。结果表明:煤的承载能力随着初始围压的上升明显提高。煤在变形破坏过程中的AE时序参数、空间分布演化特征和振幅分布均与其所处力学状态契合良好,部分AE参数在煤样变形破坏过程中产生明显突变:AE空间分布演化2次突变点对应的应力水平分别为55%和80%;能量率突变点对应的应力水平为87%;振铃计数率的突变点大致对应其峰值应力;振幅和b值的峰值分别对应峰后89%和78%左右的应力水平。根据突变点对应变形破坏阶段的不同,将其综合分为4组,作为煤卸荷破坏的前兆信息,为采用AE监测技术预防开挖过程中的动力灾害事故提供参考。
[Abstract]:In order to investigate the acoustic emission (AE) characteristics of the whole process of coal destruction and its precursor information, the unloading failure of coal samples under different initial confining pressures was tested by using MTS815 rock mechanics test system and PCI-2 acoustic emission monitoring system. The confining pressure effect of AE characteristics and the comprehensive damage precursor information based on acoustic emission are obtained. The results show that the bearing capacity of coal increases with the increase of initial confining pressure. The time series parameters of AE, the evolution characteristics of spatial distribution and amplitude distribution of coal in the process of deformation and failure all agree well with the mechanical state in which they are located. Some AE parameters have obvious mutations in the coal sample deformation and failure process. The stress levels corresponding to the two abrupt points corresponding to the evolution of the spatial distribution of the fraction AE are 55% and 80%, respectively; the stress level corresponding to the energy rate mutation point is 87%; and the abrupt point of ringing counting rate is corresponding to the change point. Corresponding to its peak stress; The peak values of amplitude and b correspond to the stress levels of 89% and 78% after the peak, respectively. According to the different deformation and failure stages corresponding to the sudden change point, it is divided into 4 groups, which can be used as the precursor information of coal unloading and damage, and provide a reference for the use of AE monitoring technology to prevent dynamic disasters and accidents during excavation.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室水利水电学院;
【基金】：国家重点基础研究发展计划资助项目(2011CB201201) 国家自然科学基金资助项目(51204113;51134018)
【分类号】：TD315

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