空区处理与残矿回采对围岩及地表影响的数值模拟分析

Numerical simulation analysis for the effects of processing goaf and extracting residual ore on the surrounding rocks and surface layers

为了提高矿山企业开采的生产效益及确保施工中设备人员的生命财产安全,采用现场声波测试试验与室内物理力学试验得出的力学参数,应用FLAC3D数值模拟软件,在空区顶板-矿柱体系简化为弹性矩形薄板-H-K体流变力学模型的基础上,分析空区处理与残矿回采对围岩及地表的影响规律。结果表明:矿区三中段充填回采过程中压应力最大值出现在Ⅲ-10开采之后,右帮壁形成了9. 8 MPa的压应力集中区;拉应力区域主要存在于充填体内,且大部分拉应力超过了充填体抗拉强度幅值0. 12 MPa;地表移动带范围内垂直方向位移保持在0～1 mm。实际施工中应采取加强充填体强度达0. 27 MPa以上或保留部分矿体支撑顶板等措施确保回采安全。

The present paper is aimed at making an analysis on how to improve the production efficiency of mining enterprises in exploitation and ensure the miners’human life security and working efficiency of the equipment installed in the process of the construction,on the condition for goaf progression and ore-residual extraction with the surrounding rock and soil surface.For the said purpose,we have gained a series of mechanical parameters from the field acoustic wave tests and the laboratory physical mechanical examinations.Furthermore,we have also managed to analyze and gain the effect of processing goaf and extracting ore-residual by simplifying the numerical simulation software FLAC3D on the basis of the assumption that the goaf roof-pillar system can be taken as the elastic rectangular thin plate-H-K rheological mode.In addition,we have been successful in measuring the density of the residual ore and the surrounding rocks with the quantity product method.Besides,we have also finished the compression strength test by using the TAW-2000 instrument and that of the tensile strength with the Brazil splitting method.All the aforementioned examination and testing results demonstrate that the maximum compressive stress can be found through extractingⅢ-10 pillar in the process of rock-filling and extraction in the third sublevel of the mining field.At the same time,the compressive stress and the tensile stress in the third sublevel of mining area surrounding the rock-filling bodies should be produced by the compressive stress of the concentration zone,with the maximum compressive stress being worked out at about 9.8 MPa over there.The tensile stress of the concentration zone mainly tends to appear in the filling body,with majority of the tensile stress,maybe,exceeding 0.12 MPa,which seems to be its ultimate tensile strength.Besides,the vertical displacement can be kept within the range of 0-1 mm in the surface displacement zone.In such a way of surface displacement,the damage wouldn’t come to happen at the surface.Thus,in conclusion,corresponding measures can be made to ensure the safety in extracting the residual ore.It is necessary to increase the tensile strength of the filling body above to 0.27 MPa or retain some pillar to support the roof to ensure the safety in extracting the residual ore.Hence,the given research results can be expected to provide valuable reference to the similar research projects.