单轴压缩下典型煤岩破坏的声发射特征研究  被引量:2

Acoustic Emission Characteristics Stucty of Typical Coal Rock Failure under Uniaxial Compression

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作  者:胡千庭[1,2] 刘荣辉[1,2] 李全贵[1,2] 钱亚楠 凌发平 Hu Qianting;Liu Ronghui;Li Quangui;Qian Ya'nan;Ling Faping(State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 40044,P.R.China;School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,P.R.China)

机构地区:[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆大学资源与安全学院,重庆400044

出  处:《地下空间与工程学报》2023年第6期1769-1781,共13页Chinese Journal of Underground Space and Engineering

基  金:国家自然科学基金资助项目(52074049)。

摘  要:矿山动力灾害的发生常伴随煤岩破裂失稳,研究煤岩破裂的演化特征将为矿山动力灾害监测预警提供理论基础。选取某矿煤系地层中常见的煤、泥岩、砂岩、页岩4种典型煤岩试样进行单轴压缩试验,研究其破坏过程的声发射特征。结果表明:振铃计数能够较好地反映煤和页岩试样各阶段的破坏规律,煤和页岩试样的累计振铃计数曲线增长拐点与其破坏过程中的塑性阶段起始点相对应,泥岩和砂岩的破坏过程的振铃计数较少,累计振铃计数曲线增长拐点出现在塑性阶段后期;煤、泥岩、砂岩、页岩试样拉伸破坏的占比平均值依次为64.97%、73.12%、84.45%、92.21%,均是以拉伸破坏为主的拉剪混合破坏;4种煤岩在破坏前各频段声发射信号的数量出现突增,煤和砂岩发生主破裂时的主导频段为Ⅲ(150~200 kHz)频段,泥岩为Ⅰ(50~100 kHz)、Ⅴ(280~330 kHz)频段,页岩主要集中在Ⅱ(100~150 kHz)、Ⅴ(280~330 kHz)频段;4种煤岩的声发射b值都大致呈现“上升-波动-下降”的变化特征,能有效反映4种煤岩的破裂过程,破坏前的下降趋势可以作为煤岩破裂失稳的重要前兆信息。The occurrence of mine dynamic disaster is often accompanied by coal rock failure.Study on the evolution characteristics of coal rock fracturing can provide a theoretical basis for the monitoring and early warning of mine dynamic disaster.Four typical coal rock samples,including coal,mudstone,sandstone and shale,which are common in coal measure strata of a mine,are selected for uniaxial compression tests to study the acoustic emission characteristics of their failure process.The results show that:The ringing counts can precisely reflect the failure law of coal and shale samples in each stage,and the increasing inflection point of cumulative ringing count curve appears at the beginning of plastic stage.In the failure process of mudstone and sandstone,the ringing count is less,and the inflection point of the cumulative ringing count curve appears in the late plastic stage.The failure modes of the four coal rock samples are mainly tensile failure and the average proportions of tensile failure of coal,mudstone,sandstone and shale samples are 64.97%,73.12%,84.45% and 92.21%,respectively.The number of peak frequencies of each frequency band shows a sudden increase before the failure.The main fracture frequency of coal and sandstone is Ⅲ(150~200 kHz),mudstone is Ⅰ(50~100 kHz) and Ⅴ(280~330 kHz),and shale is mainly concentrated in Ⅱ(100~150 kHz) and Ⅴ(280~330 kHz).The acoustic emission b-value of the four types of coal rock generally show the characteristics of "uptrend-fluctuation-decline stage".The b-value can effectively reflect the fracture process of the four kinds of coal rock,and the decreasing trend before the failure can be used as an important precursor information of the failure and instability of coal rock.

关 键 词:单轴压缩 振铃计数 破坏模式 峰值频率 煤岩 

分 类 号:TD315[矿业工程—矿井建设]

 

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