中尺度复杂岩体应力波传播特性的微震试验研究
Experimental study on characteristics of stress wave propagation in mesoscale and complex rock mass by microseismic monitoring
-
摘要: 采用全数字型多通道微震监测系统,对深部复杂采空区岩体和上部露天台阶絮渣岩体分别进行了现场爆破应力波传播特性试验,利用P波触发时间和传播距离组成的离散点进行线性拟合,得出应力波传播速度,结果显示深部复杂采空区岩体和上部絮渣岩体明显出现两个层状速度模型。利用应力波振幅和传播距离组成的离散点进行曲线拟合,并对应力波信号进行频谱分析和滤波处理,研究应力波的衰减特性。试验结果表明,应力波振幅随传播距离的增加而减小,且在数值上呈乘幂衰减;应力波衰减系数和应力波频率成正比,数值上呈三次多项式关系,高频成分应力波衰减更加明显。利用试验数据,分别计算出深部复杂采空区岩体和上部絮渣岩体的平均品质因子,计算结果分别为4.055和2.478,两者远小于一般原岩的岩体品质因子,说明复杂采空区和絮渣的存在对应力波的传播有很大影响。Abstract: By using the digital multi-channel microseismic monitoring system, the characteristics of blast stress wave propagation in deep complex and mined-out area and upper fractured rock mass are tested. The wave velocity is acquired by the curve fitting method, which uses the P wave triggering time and propagation distance. The results show that the wave velocities in deep complex and mined-out rock mass and upper coagula rock mass are obviously different. Fitted the curve by using the stress wave amplitude and propagation distance, it is found that the stress wave amplitude decreases in the form of power when the propagation distance increases. By using the signal spectrum analysis and filtering, the attenuation coefficient and frequency are in cubic polynomial relations, and the attenuation of the high-frequency wave is more obvious. The average quality factors in deep complex and mined-out area and upper fractured rock mass, are calculated and they are 4.055 and 2.478, far less than those of the original rock mass, indicating that the mined-out area and fracture have great influence on the stress wave propagation.