摘要
采用有限差程序FLAC3D对天马山黄金矿残留矿柱进行回采模拟,对矿柱进行不断的模拟开挖,直至顶板岩层发生破坏。当顶板发生破坏时,其位移发生突变,计算不收敛。因此,将监测点位移是否突变、计算是否收敛作为顶板破坏的判据。依据回采过程中围岩应力和位移的变化规律,将布设现场监测器与数值模拟的结果相结合,能够对监测点的布置进行有效优化和为预报采空区突然塌陷提供理论判据,从而提高现场监测的针对性和准确性。得出结论:①破坏首先从采空区顶板开始,该区域是围岩位移最敏感处,可作为位移突变判据的监测点,是多点位移计布置的优选位置。②矿柱回采结束后,位于采动影响范围顶部的岩层引导着应力向采空区端部区域转移,随着采空区暴露面积的增加,其端部的支承应力随之增大,但当采空区顶板岩层发生破坏时,空区顶板应力向支承压力区转移的路径发生阻断,破坏后的采空区顶部岩体重力不再向其端部传递,支承压力区的压力出现下降的趋势,表现为应力反弹现象,这种现象为现场应力监测进行采空区突然塌陷预报时提供了理论判据,因此,在采空区端部区域布置应力传感器优于其它位置。
The finite difference procedure FLAC3D was adopted to simulate the recovery of the residual pillars in Tianmashan gold mine till the destruction of the roof strata.When the roof damaged,the displacement mutation occurred and the calculations did not converge.Therefore,how the displacement mutation and calculation convergence happened can be as a criterion to judge the roof damage.According to the surrounding rock stress and displacement variation rules in stoping process,and combined with the on-site monitoring devices and numerical simulation results, a theoretical foundation is provided for the monitoring points layout optimization and forecasting for the sudden collapse of mined-out area, thereby enhancing the direction and accuracy of on-site monitoring. It is concluded that: (1)Destruction occurred from roof first. This area is the most sensitive area of surrounding rock displacement and can be as the monitoring points for judging displacement mutations, and is a preferred location for muhi-point displacement layout. (2)After pillar recovery, the top surrounding rocks affected by mining induced the stress transferring to the terminal of the mined-out area. With the exposed area of mined-out area increasing, the bearing stress in the terminals becomes larger. However, when the roof strata damage in mined-out area occurred, the path of this transferring was blocked. So the top rock weight in top of mined-out area no longer delivered downward to the terminals and then the stress in supporting area decreased, showing a rebound phenomenon of stress. This phenomenon provides a theoretical foundation of predicting the sudden collapse of mined-out area for on-site stress monitoring. Therefore, layout of stress monitoring in the terminal point of mined-out area is superior to other loca- tions.
出处
《金属矿山》
CAS
北大核心
2009年第12期56-60,共5页
Metal Mine
基金
"十一五"国家科技支撑计划项目(编号:2007BAK24B01-4)。
关键词
位移突变
应力反弹
采空区塌陷预报
Displacement mutation
Stress reaction
Forecast on collapse of mined-out area