基于矩张量反演的矿山突水孕育过程

Water inrush inoculation process in mines based on moment tensor inversion

为实现矿山突水孕育过程中岩石破裂事件的有效分析,利用河北矾山磷矿所监测的异常微震事件,引入基于数字地震学的矩张量反演方法.矿井尺度的震动位移场可表示为矩张量与格林函数的时间褶积.通过提取微震事件位移场资料,并计算格林函数(震源至传感器之间传播介质的脉冲响应),线性反演了微震事件的矩张量,并利用微震事件的破裂方位判别了其破裂类型.随后建立微震监测三维效果图,拟合出岩石破裂面发展趋势,并初步确定了突水危险区域范围.研究表明,矩张量反演方法能够计算出微震事件震源机制解,可有效反映矿山突水孕育过程中岩石破裂的形成过程及发展趋势.

To achieve the effective monitoring of rock failure events in the mine water inrush inoculation process, a moment tensor inversion method based on digital seismology was introduced to process abnormal microseismic events monitored in Hebei Fanshan Phosphate Mine. The vibration displacement field in the mine scale could be expressed as the convolution of moment tensor and Green＇s function. The moment tensor was linearly inversed through extracting displacement data from the microseismic events and cal- culating the Green＇s function （pulse response of transmission medium between the source and sensors）. Then, the type of ruptures was distinguished by analyzing the fracture azimuth of microseismic events. As a result, a 3D effect picture of the microseismic monitoring area was built to fit the rock failure surface, predict its development trend, and demarcate the water inrush danger zone preliminarily. Research results show that the moment tensor inversion method can be used to calculate a series of focal mechanism solutions and can reflect the rock failure in the mine water inrush inoculation pocess and development trend effectively.