砂岩单轴压缩微震响应小波包能谱特征  

Characteristics of Wavelet Packet Energy Spectrum on Micro-Seismic Activities of Sandstone Samples under Uni-axial Compressive Tests

作　　者：雷文杰[1,2] 王洪栋[1] 

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454000 [2]中原经济区煤层(页岩)气河南省协同创新中心,河南焦作454000

出　　处：《地下空间与工程学报》2015年第5期1111-1115,共5页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51374094;51374093;40872191);贵州省省长基金((2011)10号)

摘　　要：选取砂岩岩样,通过装有ESG微震监测系统的MTS液压伺服试验机进行单轴压缩实验,分析在加载模式下的岩石强度及变形破坏特征。运用小波包能量谱理论,提取了突变信号的频带能量和事件数,获得了砂岩单轴压缩条件下的应力应变曲线以及应力应变过程曲线中4个阶段的微震响应特征。在初始压密和弹性阶段,没有微震信号、频带归一化能量为零、事件数为零;在应力屈服阶段,微震信号多、频带归一化能量大、有大量事件数产生;在破坏阶段,微震信号丰富、频带归一化能量达到峰值后降低、事件数减少。砂岩破裂微震信号频率响应主要集中在375-625 Hz。由于岩石每个变形阶段具有不同的微震响应特征,因此,可用微震动态响应小波包能谱特征来表征岩石的微观损伤演化和预测现场工程岩体的宏观断裂失稳过程。The typical sandstone samples were carefully selected and the uni-axial compression tests by MTS hydraulic servo testing machine were carried out that the micro-seismic activities were responded by ESG micro-seismic monitoring system,the characteristics of rock strength and deformation were analyzed under the loading mode. The frequency band energy and micro-seismic events were extracted by decomposition and reconstruction of Wavelet packet,the stress-strain curve of sandstone samples under uniaxial compression as well as the characteristics of micro-seismic signals at four stages of the stress-strain curve was obtained. It is found out that the micro-seismic signals seldom happen in the initial consolidation and the elastic stage,the frequency band energy is zero,no events have been produced; The micro-seismic activities instantly occur in the yielding stage,the frequency band energy increases up to the peak of the maximum compressive strength,a large number of events ae generated; The micro-seismic signals are rich,the normalization of frequency band energy reduces in the broken stage,the number of events reduces after arriving the peak. It shows out that the frequency ranges of micro-seismic activities are mainly concentrated on 375-625 Hz. Due to the differences existed in micro-seismic activities in the four different stress stages,the energy spectrum of Wavelet packet on micro-seismic activities can be used to study micro-damage evolvement and predict macro-destabilization of engineering rock body.

关 键 词：微震 单轴压缩 归一化频带能量 事件数 小波包能量谱 

分 类 号：X936[环境科学与工程—安全科学]