煤矿冲击地压的微地震监测研究

A study on microseismic monitoring of rock burst in coal mine

为了研究煤矿冲击地压与岩层在三维空间破裂之间的关系,进而探索依据岩层破裂规律预测和预报冲击地压的可能性,文中采用自行研制的防爆型微地震定位监测(MS)系统,基于定位原理,监测了山东华丰煤矿冲击地压煤层(四层煤)及其解放层(六层煤)开采过程中的岩层破裂过程和二次应力场分布变化的过程,得到了如下结论:冲击地压的发生与岩层破裂密切相关,四层煤下顺槽处于六层煤顶板破裂区的外边缘时,正处于高应力区内,在此处掘进容易引发冲击地压,必须将六层煤下顺槽位置向实体煤侧移动20 m以上,或将四层煤下顺槽位置内移20 m以上,才能消除四层煤的冲击地压;六层煤和四层煤开采时,工作面前方断层活化的距离分别为250 m和350 m左右,根据这一距离,及时对断层带进行卸压处理,可以消除由断层带引发的冲击地压;监测显示了工作面周围岩层的三维破裂形态和范围,为矿井确定防水煤柱的高度提供了可靠的依据;监测证明了厚层砾岩的破裂、断层活化、采场附近关键层的破裂是引起冲击地压的主要原因,证明了所研制的硬件和定位软件具有较高的精度和实用性,可以在煤矿和边坡、隧道等领域应用.

Abstract By using the underground microseismic monitoring （MS） system in Huafeng Coal Mine of China, we have studied the relationship between strata fracturing and rock burst in underground coal mine, and discussed the possibility of forecasting rock burst based on the rules of strata fracturing monitored by MS. This paper presents the dynamical processes of strata fracturing and mining stress arround the longwall face while mining No. 4 seam （strong burst seam） and No. 6 seam （under No.4 seam for unloading）. The result shows that the high stress zone is close to the fractured zone. When the maingate of No. 4 seam is in the fractured roof zone of No. 6 seam, rock burst never happens during developing maingate and mining of No. 4 seam. If the maingate of No. 4 seam is out of the fractured roof zone of No. 6 seam, rock burst would happen during developing and mining of No. 4 seam. The beginning reaction distances of faults in front of the longwall face are 250 m and 350 m, respectively of No. 6 and No. 4 seam. Based on the distances, it is possible to unload in the fault zone to prevent rock burst. MS monitoring results also show the 3-D shape and scale of strata fracturing, which are very useful to determine the height of water-proof in coal mine. The MS monitoring results have proved that heavy massive strata fracturing and fault reaction are the main reasons of rock burst in the Huafeng Coal Mine. The good location results show that the MS monitoring system and locating software can be used in coal mines and tunnels for monitoring rock mass fracturing.