陡倾结构金属矿山岩层移动和地表变形的离散元模拟研究

Discrete Element Numerical Study on Strata Movement and Surface Deformation in the lron Mine with Steep Dip Structure

以金山店铁矿东区为例,采用离散元软件UDEC,结合地表监测成果,从岩体破坏、岩层移动、地表变形3个方面开展陡倾地质结构下金属矿山岩层移动和地表变形机理研究。研究结果表明:随着采矿的推进,回采区顶部垮塌和张拉破坏贯通区范围不断扩大,岩体塑性变形破坏逐步加剧;地表沉降位移和水平位移随着各分段向下开挖而不断增加,在-680 m开采水平下,地表沉降位移最大值约72.6 m,水平位移最大值约29.9 m;由于陡倾结构面的存在,上盘的变形破坏范围明显大于下盘,上盘岩层移动表现出倾倒特征,下盘岩层移动表现出剪切-滑移特征;在采矿初期,移动角和陷落角较大,随着采矿的进行,角度不断减小,开采至-382 m水平后趋于稳定;实测地表变形特征和变化趋势与数值模拟结果基本相符。研究结果可为其他具有陡倾结构的金属矿山开采提供借鉴。

Taking the eastern area of Jinshandian Iron Mine as an example,the discrete element software UDEC combined with surface monitoring results were used to study on the mechanism of rock strata movement and surface deformation in metal mines with steep dip structures from three aspects of rock failure,rock movement,and surface deformation.The research results indicate that as mining proceeds,the range of top collapse and tensile failure in the mining area continues to expand,and the plastic deformation and failure of the rock mass gradually intensify.The surface settlement displacement and horizontal displacement continuously increase with the downward excavation.At a mining level of-680 m,the maximum surface settlement displacement is about 72.6 m,and the maximum horizontal displacement is about 29.9 m.Affected by the steep structural plane,the deformation and failure range of the hanging wall is significantly larger than that of the footwall.The movement of the hanging wall rock strata exhibits tilting characteristics,while the movement of the footwall rock strata exhibits shear-slip characteristics.In the early stages of mining,the angle of movement and subsidence is relatively large.As mining deepens,the angle continuously decreases and eventually stabilizes at the mining level of-382 m.The measured surface deformation characteristics and trends are basically consistent with the numerical simulation results.The research results can provide reference for the mining of other metal mines with steep dip structures.