思山岭铁矿地应力分布规律与采场结构参数优化

In-situ Stress Distribution Characteristics and Optimization of Stope Structure Parameters in Sishanling Iron Mine

采用水压致裂法分别测量思山岭铁矿围岩与矿体地应力,分析围岩与矿体地应力分布规律及其差异。结果表明:围岩与矿体地应力均随埋深增加近线性增大,水平最大主应力始终为第一主应力,方向近NEE向;围岩与矿体水平主应力差值均较大,埋深超千米时最大与最小主应力比值分别为1.58与1.46,思山岭铁矿处于强各向异性高应力状态。围岩地应力略高于矿体地应力,千米以深时围岩水平主应力约是矿体水平主应力的1.06倍。基于地应力分布规律与矿体层理,将思山岭铁矿40 m×40 m×60 m(长×宽×高)的方形采场优化为80 m×20 m×60 m的长条形采场,模拟结果显示长条形采场开挖后的应力、位移、塑性区分布均优于方形采场,进一步提出了深埋高应力层状矿体的采场结构参数设计方法。

The hydraulic fracturing method was used to measure the in-situ stress of surrounding rock and ore body in Sishanling iron mine.The in-situ stress distribution characteristics of surrounding rock and ore body were analyzed.The results show that the in-situ stress of surrounding rock and ore body increase linearly with increasing burial depth.The maximum horizontal principal stress is always the first principal stress in a direction close to NEE.Besides,the difference between the maximum and minimum principal stress of the surrounding rock and the ore body was large,and the ratio of the maximum principal stress to the minimum principal stress is 1.58 and 1.46 when the burial depth exceeds 1000 m respectively,which indicates that the Sishanling iron mine was in a significant anisotropic stress state.Meanwhile,the in-situ stress of the surrounding rock was higher than that of the ore body,and the horizontal principal stress of the surrounding rock is approximately 1.06 times that of the ore body at a depth greater than 1000 m.Based on the in-situ stress distribution characteristics and ore body bedding properties,the square stope of 40 m×40 m×60 m(length,width and height)was optimized to a long strip stope of 80 m×20 m×60 m.The simulation results showed that the stress,displacement and plastic zone distribution after excavation of the long strip stope was better than that of the square stope.Furthermore,a stope structure parameter design method for deep buried high-stress layered ore body was proposed.