南芬露天采场楔形滑坡机理及滑动力监测预警分析

近些年,南芬露天铁矿开采深度越来越大,局部已经形成552 m高边坡(标高142~694 m)。由于主采场断面呈"V"字型展布,采场底部空间日益狭小,滚石和滑坡灾害有效避险空间丧失,严重威胁人员和机械的安全。针对上述问题,矿山启动了三期扩帮四期开采工程,受老滑坡体影响,下盘扩帮过程中连续3年发生了多次局部滑坡灾害。针对"2016-1101滑坡"深部滑动力监测预警曲线进行分析,结合现场调查,判断其滑坡成因和破坏模式;采用赤平极射投影法分析了滑坡发生机理和滑坡体安全系数;利用FLAC3D中的Fish语言构建了具有负泊松比特性的恒阻大变形锚索(NPR)数值分析模型,并对"2016-1101滑坡"进行数值建模分析,将实际监测结果和模拟结果进行对比,发现二者具有显著的一致性,为其他类似边坡的滑坡机理分析和数值模拟计算提供了理论和实践依据。

Analysis of wedge-shaped landslide mechanism and sliding force monitoring warning in Nanfen open pit iron mine

In recent years,as the exhaustion of shallow resources and the increase of mining depth,the local slope height reaches 552 m (elevation 142-694 m).Because of the “V” shape of main pit section,the space on the bottom of pit becomes narrow and suffers the risks of rock rolling,landslides and other disasters.These are serious threats to personnel and mechanical safety.To overcome the problems above,Nanfen mine started the new phase of slope expansion and mining.In the last three years,landslide disasters occurred many times during the slope expansion due to the old landslide bodies.This paper uses the “Landslides 2016-1101” case to analyze the in-situ sliding force monitoring and early warning system and establish the landslide causes and failure models.Then,the Stereographic Projection Method is employed in the analysis of landslide mechanism and safety factor.Finally,a numerical modeling analysis by FLAC3D is preformed,particularly involving the Negative Poisson’s Ratio cable (NPR) model by Fish language programming.The case of “Landslide 2016-1101” is simulated by numerical calculation,and the result shows a remarkable consistency comparing with the in-situ data.The research may provide a theoretical and practical basis for similar engineering problems.