金川二矿区1150m中段水平矿柱的屈服破坏过程

Yield process of the 1150-m horizontal jamb in Jinchuan No. 2 Mine area

金川二矿区采用大面积不留矿柱回填采矿法,开拓出不同标高的两个采矿面,其间为水平矿柱。2004年,水平矿柱东薄西厚,东部二盘区厚度最小,约32 m。通过建立三维有限元弹塑性力学模型,模拟计算了水平矿柱上各盘区的屈服破坏过程。模拟结果表明:水平矿柱的屈服破坏从东部开始,然后扩展到西部,2005年的水平矿柱已基本上整体进入破坏状态;水平矿柱上各盘区在2006年及以后的开采中将很快出现显著沉陷,这与矿区2006年的现场观察相符;已经屈服的水平矿柱对上盘围岩中巷道工程的抵顶作用将衰减,不会成为未来巷道破坏的主要影响因素,故没有必要调整水平矿柱上各盘区的既定采矿方案。

In Jinchuan No.2 Mine area,two mining levels with different altitudes were resulted from the backfilled mining in large hypogeal area without micro-jambs,and the ore-body between them called a macro-horizontal jamb was distinguished as seven mechanized panels.In 2004,the thickness of the east part was smaller than that of the west part in the macro-horizontal jamb,especially the smallest thickness appeared at the eastern second mechanized panel was only about 32 m.A three-dimensional finite element model was constituted to simulate the yield process of the macro-horizontal jamb in the tectonic stress field caused by continuous mining.It was indicated that the yield process began at the east firstly,then spread to the west,and in 2005,all mechanized panels besides the seventh one attained the destroyed situation within the macro-horizontal jamb.Based on the calculated results,it was predicted that in 2005 the mechanized panels would appear obvious submergence phenomena,which had been already proved by the local observations in 2006,and it was considered that the counteractive effect of the macro-horizontal jamb with high stress concentration ever resulted in the worst structural distortion of drifts would decline quickly and become a minor factor.Therefore,it was advised that choosing a new mining plan with respect to all mechanized panels should not be necessary to the macro-horizontal jamb in the future.