【摘要】 通过现场进行的爆破震动试验及矿山微震监测,以爆破震动波波速、振幅及频率等为主要分析指标,研究了矿井采动影响下煤岩特性改变对冲击震动波传播微震效应的影响规律.研究表明,随工作面开采时采空区垮落、破裂范围扩大及覆岩性质的强度弱化,各爆破震动P波平均波速、峰值振幅平均值、P波初至平均频率等微震参量均有较大程度降低.其中,波速平均值下降率最大达69.8%,振幅平均值最大降幅高达92.2%,P波初至平均频率最大降幅也达60.0%以上.试验结果揭示了覆岩结构及性质改变对震动波传播衰减和能量耗散的影响特征,为矿山微震监测的定位修正和参量优化提供了基础数据,更为研究采动诱发矿震动载的震动效应及采取有效冲击防治对策提供重要试验依据.更多还原

【Abstract】 The changes of seismic characteristics in strata associated with longwall coal mining process are studied using on-site blasting tests and microseismic monitoring techniques.The seismic characteristics were obtained from analysis of seismic velocities,amplitudes and frequency contents in response to a series of blasts conducted at different mining stages.The results show that the average P-wave velocities,mean values of comb.max.amplitudes and frequencies of the seismic compression waves are all reduced significantly with roof caving,goaf development and intensity weakening of overlying strata associated with mining process.In an area where the strata are fully caved,the fractures can decrease the P-wave velocities,comb.max.amplitudes and frequencies by about 69.8%,92.2% and over 60.0%,respectively.The deduction of the seismic parameters reveals the effect characteristics of the variation of the overlying strata structure to the seismic wave transmission and energy dissipation.These results have provided evidence of a strong correlation of seismic velocity and energy to the strata deterioration processes.This has suggested that in order to obtain accurate event location,the seismic velocities must be adapted in response to the rock fracture development.Reliable seismic event locations will greatly benefit the further study on seismic effort of mining-induced tremor and prevention of rock burst.更多还原