金川二矿区+1000m中段水平矿柱回采方法研究

Study on Mining Method of Horizontal Pillar in the Middle Section of +1 000 m in Jinchuan No.2 Mining Area

针对金川镍矿二矿区+1000 m中段开采实际,利用ANSYS建立大型三维数值模型,基于FLAC3D进行数值模拟计算,对+1000 m中段水平矿柱回采期间充填体及地表的应力和位移变化趋势进行分析,综合评价了二矿区+1000 m水平矿柱回采期间充填体的稳定性。研究结果表明:(1)在回采过程中,应力显现明显,上下盘累积位移量较大;当水平矿柱厚度为20~30 m时,矿柱应力变化显现剧烈,最大主应力值达到峰值;(2)充填体是从围岩接触带部分开始破坏,向充填体中央发展,靠近上盘的充填体比靠近下盘的充填体破坏严重;(3)提出了2种回采方案,并进行了对比分析,结果显示在回采过程中,应力显现明显,上下盘累积位移量较大,2种方案均未出现大面积坍塌灾变的现象。通过对比综合应力和位移变化曲线可知:方案二优于方案一,但2种方案在回采矿柱末期均面临着水平矿柱大面积塑性破坏和局部失稳的危险。

The ore body in the No.2 mining area of Jinchuan mine is exploited at the same time in the middle section of+1000 m and+850 m.With the continuous development of mining,some technical problems in the recovery stage of the horizontal pillar in the middle section of+1000 m are also highlighted.In the face of more and more serious actual situation,it is necessary to study the stability of horizontal pillar and filling body thoroughly.A detailed field investigation was conducted on the mining environment of the horizontal pillar in the middle section of+1000 m.On this basis,using the ANSYS and FLAC3D numerical simulation software,the trend analysis of the stress and displacement of the filling body and the ground surface during the recovery of the horizontal ore pillar in the two mining area was analyzed,and the underground filling in the two mine area was revealed.The dynamic pressure distribution law of the body and the ground surface during the whole mining process,the stability of the filling body during the mining of the+1000 m level pillar in the No.2 mining area was synthetically evaluated,and the stability of the 700 m and+850 m middle section mining was predicted by this method.The following conclusions are mainly obtained:During the mining process,the stress appears obviously,the accumulative displacement of the upper and lower plates is larger.When the thickness of the horizontal pillar is 20~30 m,the stress changes in the pillar,the maximum principal stress reaches the peak,the plastic failure area is in the middle of the rich ore body and has the through phenomenon,and the plastic failure of the pillar is all when the thickness of the horizontal pillar is 20 m.The filling body begins to destroy from the part of the contact zone of the surrounding rock and develops to the center of the filling body,and the filling body on the upper plate is seriously damaged than the filling body on the foot wall.According to the mining practice in the middle section of+1000 m in the two mining area,two kinds of mining schemes are put forward and compared.The results show that during the mining process,the stress appears obviously,the accumulative displacement of the upper and lower plates is larger,and the two schemes have not appeared the phenomenon of large area collapse.Compared to the comprehensive stress,displacement and plastic failure area,the scheme two is better than the scheme one,but the two schemes are faced with the danger of large area plastic failure and local instability of the horizontal pillar at the end of the pillar mining.