大采高综放面底板破坏深度的高精度微震监测研究

Study on high precision microseismic monitoring of bottom failure depth of fully mechanized top coal caving mining face

煤矿底板突水事故严重威胁着矿井的安全生产,煤层采动引起底板隔水层破坏是诱发突水的重要原因,而进行底板破坏深度探测是预防突水的有效技术手段。以何家堡煤矿为例,将高精度ARAMIS M/E微震监测技术应用于特厚煤层大采高综放面的底板破坏中,首先在工作面两侧巷道的底板锚杆上以菱形方式布置6个检波器探头,然后用最小二乘法选择最佳波速参数,用振动持续时间法计算微震能量,最终通过分析微震事件的能量、频次和密集程度确定煤层底板岩体的破坏范围。为探讨微震监测底板破坏深度的准确性,采用塑性力学中解析法进行理论计算。结果表明,微震监测技术与理论计算结果较接近,验证了微震监测应用于探测底板破坏深度的可靠性。

Safety of mine production was seriously threatened by floor water inrush, the main reason of water inrush was damage of bottom water resisting layer caused by coal mining and detecting depth of destroyed floor was an effective technical mean to prevent water inrush. Taking Hejiabao mine as an example, high precision ARAMIS M/E microseismic monitoring technique was applied in floor destruction of fully mechanized top coal caving face with large mining height in extra thick seam. Firstly, 6 detector probes were arranged with diamond shape in floor bolt of roadway on both sides of working face. Then, optimum wave velocity parameters were selected by least square method and microseismic energy was calculated by vibration duration method. Finally, the failure range of coal seam floor rock mass was determined by analyzing energy, frequency and intensive degree of microseismic events. In order to discuss accuracy of depth of destroyed floor with micro seismic monitoring, analytic method in plastic mechanics was adopted to carry out theoretical calculations. The results showed that microseismic monitoring technique was close to theoretical calculation, which verified reliability of using microseismic monitoring in detecting failure depth of floor.