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一般而言,岩石力学问题在工程尺度上是裂隙岩体的力学行为问题,尤其是裂隙岩体在荷载作用下的强度分布、变形特征及破坏演化规律。以软岩(煤岩)为研究对象,对完整煤岩进行预加载获取裂隙煤岩体试件,并在统计意义上将其划分为含单一裂隙及含多条裂隙煤岩体,进而利用试件在加载破坏过程中的声发射现象及其最大振幅的分布规律,研究完整煤岩及裂隙煤岩体在单轴加载条件下的破坏演化过程及差异。研究结果表明:定量指标b值能够描述破坏演化过程中AE事件最大振幅的分布规律,其值越大,破坏裂隙扩展所受的阻碍越大;不同应力水平条件下,随着荷载的增加,b值整体呈降低趋势;在相同应力水平条件下,内部所含裂隙越多,b值越大;完整煤岩及裂隙煤岩体在破坏演化过程中b值的变化规律显示,当b值的降低幅度趋于平缓时,可作为试件即将破坏的前兆。研究成果可为利用声发射技术进行现场监测预警提供试验依据。
In general, the rock mechanics problem is the mechanical behavior of fractured rock mass at engineering scale, especially the strength distribution, deformation characteristics and failure evolution of fractured rock mass under load. Taking soft rock (coal and rock) as the research object, intact coal rock is preloaded to obtain fractured coal and rock mass specimen, and is divided into a single fracture and a number of fractured coal and rock mass in a statistical sense, and then use the test Acoustic emission and its distribution of maximum amplitude during the process of loading failure are studied to study the evolution process and difference of failure of intact coal and fractured coal and rock mass under uniaxial loading. The results show that the b value of quantitative index can describe the distribution rule of maximum amplitude of AE events during the process of failure evolution. The bigger the value is, the more obstructive the crack propagation will be. Under different stress levels, with the increase of load, b The value of b decreases with the increase of b value, and the b value increases with the increase of bifurcation in the same stress level. The change of b value of intact coal and fractured coal and rock mass during the process of failure and evolution shows that when b value decreases Amplitude tends to be gentle, can be used as a precursor to the destruction of the specimen. The research results can provide experimental basis for the use of acoustic emission technology for on-site monitoring and early warning.