单轴压缩下某弱胶结砂岩声发射特征及破坏形式

为研究小纪汗煤矿弱胶结砂岩的声发射特征和破坏形式，对取自该矿的砂岩试件开展单轴压缩试验，并进行声发射监测。试验表明：对6个试件的声发射特征曲线归纳为崩裂型和破裂型2种，前者在弹性阶段和微裂隙稳定发展阶段声发射活动较少，屈服阶段后期至破坏前声发射活动骤增，破坏后仍有部分声发射活动；后者弹性阶段和微裂隙稳定发展阶段声发射活动强于前者，屈服阶段声发射活动出现大幅阶梯增长（至峰值），峰值前有声发射平静期。试件破坏形式，可分为X型共轭破坏和单斜面剪切破坏2种，前者对应崩裂型曲线，试件强度较大；后者对应破裂型曲线，试件强度较小。研究结论对高强度开采条件下顶板变形失稳的预测具有指导意义。

Acoustic Emission Characteristics and Failure Patterns of a Weak Cemented Sandstone under Uniaxial Compression:Xiaojihan Coal Mine in Shannxi as a Case

In order to research the acoustic emission characteristics and failure patterns of the weak sandstones，uniaxial compression tests together with the acoustic emission monitoring tests on specimen from Xiaojihan Coal Mine are conducted.The test indicated that the characteristic curves of the acoustic emission of six specimens were summarized as the splitting type and the fracturing type.For splitting type curves，the acoustic emission events occurred rarely in the linear elastic and stable development of micro-cracks stage，while they occurred rapidly from the later yielding stage to earlier destruction stage，and still existing after the destruction stage.For fracturing type curves，in linear elastic and stable development of micro-cracks stage more acoustic emission events occurred than those of the splitting type curve，and in yielding stage acoustic emission events increased stepwise until the peak strength，moreover acoustic emission quiet period existed before the peak strength.Furthermore，the failure forms can be divided into single shearing failure and X-type conjugate failure.For single shearing failure，the specimens show higher strength relatively，and its form of failure generally corresponded to acoustic emission characteristic curve of splitting type.Meanwhile，for X-type conjugate failure，the specimens show lower strength，and its form of failure generally corresponded to acoustic emission characteristic curve of fracturing type.The results are of great significance for prediction of the roof deformation failure under high intensity mining.