摘要
通过开展不同埋深灰岩的常规单轴试验,获取灰岩破坏过程中的应力—应变曲线和声发射时域特征参数。利用弹性能量指数WET、变形脆性指数Kε和线弹性能We指标,判别不同埋深灰岩岩爆倾向性。通过分析灰岩破坏过程的声发射特征参量及其变化规律,建立了发生岩爆的前兆信息特征。结果表明:随着埋深梯度递增,岩石岩爆倾向逐级增强,当埋深达1000 m以上时,灰岩具有强岩爆倾向;不同埋深灰岩受压破坏过程中声发射累计能量—时间变化曲线可划分为平稳、增长和破坏3个阶段,随着灰岩岩爆倾向逐级增强,岩爆破坏释放的能量越大;各埋深灰岩试样主频主要为90~180 kHz的低频带,同时中等和强岩爆倾向具有270~330 kHz高频率次主频;各埋深梯度下灰岩声发射能率分形特征与其内部裂隙演化规律具有一致性,不同埋深灰岩岩爆倾向性由弱到强的分维值演化模式按"升维—波动—降维"到"平稳—降维"演化。研究结果可为深部开采预警岩爆提供理论依据。
With the increasing demand for mineral resources,deep mining is becoming more and more popular in mines and rock burst disasters are becoming more and more frequent.Rock burst warning and prevention have become one of the major safety issues that need to be solved in the field of geotechnical engineering in the world today.The acoustic emission of rock is an effective carrier to reflect the internal damage information of rock.The study on the characteristics of acoustic emission parameters in the process of rock burst rupture and instability provides a theoretical basis for the early warning of rock burst by acoustic emission parameters in deep mining.Limestone core samples were obtained from the same borehole at different depths in a copper mine.By carrying out conventional uniaxial tests of limestone with different buried depths,the stress-strain curve and acoustic emission time-domain characteristic parameters in the limestone failure process were obtained;the elastic energy index WET,deformation brittleness index Kεand linear elastic energy We index were used to distinguish Limestone rock burst tendency of different buried depths;By analyzing the characteristic parameters of acoustic emission in the failure process of limestone and their changing laws,the precursor information characteristics of rock bursts were established.The results show that with the depth gradient increases,when the buried depth is more than 1000 m,the limestone has a strong rock burst tendency.The accumulative energy-time variation curve of acoustic emission during the compressive failure of lime stones at different depths can be divided into three stages,namely,steady stage,growth stage and failure stage.The stable stage is in the initial compaction stage of limestone.As the tendency of limestone rock burst becomes stronger,the axial strain corresponding to the acoustic emission energy at this stage becomes smaller.The growth stage is the expansion stage of new fissures in the limestone rock.The cumulative acoustic emission energy changes with the depth of the burial depth and presents a“step-like”evolution to a“smooth”growth form,and the failure stage is the stage of macroscopic cracks causing rock mass destruction.In this stage,as the tendency of limestone rock burst gradually increases,the energy released by rock burst increases.The dominant frequency of each deep limestone sample is mainly the low frequency band of 90~180 kHz,while the medium and strong rock burst tendencies have a high frequency secondary frequency of 270~330 kHz.The fractal characteristics of the acoustic emission energy rate of limestone under the depth gradient are consistent with the evolution law of its internal fissures.The evolution mode of fractal dimension value of limestone rock burst tendency from weak to strong at different depths is based on“up-dimension-wave-dimension reduction”.The evolution of“steadydimensional reduction”can provide a theoretical basis for early warning of rock burst in deep mining.
作者
曾强
黄小荣
王晓军
陈青林
刘健
龚囱
ZENG Qiang;HUANG Xiaorong;WANG Xiaojun;CHEN Qinglin;LIU Jian;GONG Cong(School of Resources and Environmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;Jiangxi Provincial Key Laboratory of Mining Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;No.1 Nonferrous Geological Team,Jiangxi Bureau of Geology,Yingtan 335000,Jiangxi,China)
出处
《黄金科学技术》
CSCD
2021年第6期863-873,共11页
Gold Science and Technology
基金
国家自然科学基金青年基金项目“渗透压力作用下岩石蠕变声发射震源主频特征及其能量机制”(编号:51704128)
江西省地质局科技计划项目“深井工程勘察地应力岩爆倾向性分析应用研究”(编号:2021AA21)联合资助。
关键词
岩石力学
岩爆倾向
声发射
关联维数
破裂机理
rock mechanics
rock burst tendency
acoustic emission
correlation dimension
fracture mechanism
