眼前山铁矿露天转地下开采过程中料仓稳定性研究

Study of Ore Bin Stability of Yanqianshan Iron Mine During the Transfer From Deep Open-casting to Underground Mining

针对眼前山铁矿露天转地下开采过程中西南帮高边坡上料仓稳定问题,考虑断层的影响,建立了数值计算模型。利用FLAC软件对地下开采过程中料仓稳定性和料仓地表沉陷进行了研究。分别分析了开采到-320 m和-500 m水平时,塑性区分布和拉应力分布规律,并以地表沉降变形区范围来评定料仓稳定。数值计算结果表明,随着开挖的深入,料仓稳定性下降。在开采到-320 m水平时,料仓地表倾斜值在3 mm/m内,边坡整体稳定、塑性区主要集中坡脚并且开展范围小,料仓稳定。当开采到-500 m水平时,塑性区和拉应力区几乎分布整个坡体,断层存在对料仓影响显著。边坡整体滑坡性小,但坡体内部应力重新分布,导致地表沉陷值增大,料仓失稳。

A calculation model for ore bin stability which in the southwest top slope of Yanqianshan iron mine was built during the transfer from deep open-casting to underground mining and based on the effect of rock fault.The FLAC software was used to study the ore bin stability and the surface subsidence around it.The plastic zone distribution and tension stress variation laws were analyzed under the conditions of-320 meters and-500 meters mining levels and with the subsidence as the standard to evaluate the ore bin stability.Numerical results showed that the ore bin stability decreased as the digging depth increased.When the digging came up to-320 meters,the ore bin surface subsidence within 3 mm/m and the plastic zone mainly appeared at the foot of slope with small range,indicating that ore bin and slope stable.When the digging came up to-500 meters,the plastic and tension stress zone nearly appeared all around the slope,and the influence of rock fault was significant.Overall landside slope possibility small,but slope body internal stress was redistributed,resulting in subsidence increased and ore bin instable.