【摘要】 从能量释放的角度讨论了深部岩体开挖激发微地震的机制.研究表明,伴随着爆破破岩新自由面形成而发生的岩体弹性应变能释放属于瞬态过程,高地应力条件下爆破开挖产生的微地震由爆炸荷载和初始地应力(开挖荷载)瞬态释放耦合作用引起.地应力瞬态释放激发的微地震可成为周围岩体振动的主要组成部分,这有赖于岩体自身的蓄能能力、岩体开挖方式及开挖面的大小.通过瀑布沟地下厂房爆破开挖过程中实测围岩地震信号的时能密度和幅值谱分析,对地应力瞬态释放激发的微地震进行了识别.耦合地震信号的低频成分主要由初始地应力瞬态卸荷引起,而高频成分主要由爆炸荷载引起.应用数字信号处理的FIR滤波方法对耦合振动信号进行了初步分离,数值计算验证了分离结果的可靠性.更多还原

【Abstract】 The mechanism of triggered microseism by excavation of deep rock mass is discussed from the view of energy release.Results reveal that the elastic strain energy release of rocks,accompanied with the formation of new free surface during the rock fragmentation by blasting,is a transient process;and in highly stressed rock mass,the triggered microseism by blasting excavation is attributed to the coupling of blasting load and transient release of in-situ stress(TRIS).The TRIS-triggered microseism could become absolutely the main component of total vibration,which depends on the storage capacity of rock energy,the excavation method and the size of excavated surface.In combination with the blasting excavation of an underground powerhouse in the Pubugou Hydropower Station,the microseism excited by TRIS is identified through time-energy density analysis and amplitude spectrum analysis of monitored microseismic signals in surrounding rocks.Results indicate that lower frequency component in the coupled microseism results more from TRIS than from blasting load,and higher frequency component originates from the blasting load alone.The coupled microseismic signals are separated by employing the finite impulse response(FIR) filter,and separated waves agree very well with numerical simulation results.更多还原