微震监测技术在大直径超深井筒施工中的应用

Application of Microseismic Monitoring Technology in Large Diameter and Ultra Deep Shaft Construction

某铁矿副井深度超过1 300 m,高地应力给竖井施工带来较大的地压灾害风险。为了掌握井筒深部岩体开挖后破坏程度,进行了微震监测。通过在竖井马头门布置微震监测系统,获取井下微震信号并进行识别与分析,提取了岩体破坏产生的地震波,爆破、矿石移动和机车运动等产生的振动信号,对各类信号的特征与类别进行了分析;获得微震定位、微震事件时间分布及震级相关参数。研究表明:凿井期间在马头门布置微震监测系统对井筒的围岩破坏情况进行实时监测具有可行性;爆破震动是诱发微震活动的主要因素,优化爆破参数、减小爆破震动对围岩的扰动和破坏非常必要;井筒深部岩体微震事件主要分布在开挖体周围2 m左右深度的围岩内,工程震级最大为1.05,井壁围岩稳定,发生失稳风险小。

The depth of the auxiliary shaft of an iron mine is more than 1 300 m, and the high ground stress brings great ground pressure disaster risk to the shaft construction. In order to grasp the damage degree of deep rock mass in the shaft after excavation, microseismic monitoring was carried out. By arranging a microseismic monitoring system at the ingate of the shaft, the underground microseismic signals are obtained, identified and analyzed, the seismic waves generated by rock mass destruction, vibration signals generated by blasting, ore movement and locomotive movement are extracted, and the characteristics and categories of various signals are analyzed;The parameters of microseismic location, time distribution of microseismic events and magnitude are obtained. The research shows that it is feasible to arrange a microseismic monitoring system at the ingate to monitor the damage of the surrounding rock of the shaft in real time during shaft sinking;Blasting vibration is the main factor inducing microseismic activity. It is very necessary to optimize blasting parameters and reduce the disturbance and damage of blasting vibration to surrounding rock;Microseismic events in the deep rock mass of shaft are mainly distributed in the surrounding rock with a depth of about 2 m around the excavation body.The maximum magnitude of the shaft project is 1.05. The surrounding rock of the shaft wall is stable and the risk of instability is small.