某铁矿采空区稳定性的数值模拟分析

Numerical Simulation Analysis on Goaf Stability of an Iron Mine

某铁矿I号铜矿带浅部采用浅孔房柱法开采,经过近7 a的开采,从800 m分段至880 m分段共形成145个采空区,采空区内存在大量尺寸不等的间柱、点柱、顶、底柱,部分采空区已贯通,空实比约为3∶1,采空区体积之和约为95.2万m3。为探讨该采空区的稳定性,在现场调查、室内岩石力学实验及矿岩体质量分级的基础上,采用FLAC3D有限差分法,对矿体开采至不同中段时采空区、矿柱等的稳定性及采空区对地表充填制备站的影响进行研究。结果表明:145个采空区中有18个采空区顶板存在明显的拉应力,且位移量也相对较大,如不及时处理,随着矿柱荷载的不断增加,会导致矿柱失稳破坏,最终引发一系列的地压问题。研究成果为矿山采空区的治理提供了理论依据。

The shallow part of No.1 copper belt of an iron mine is mined by shallow hole room and pillar method.After nearly seven years of mining,145 goafs have been formed from 800 m to 880 m.There are a large number of pillars,point pillars,top and bottom pillars in the goafs.Some of the goafs have been connected,the ratio of air to solid is about 3:1,and the total volume of mined out areas is about 952 000 m3.In order to explore the stability of the goaf,on the basis of field investigation,indoor rock mechanics experiment and rock mass quality classification,FLAC3 D finite difference method is used to study the stability of goaf and pillar when the ore body is mined to different middle sections and the influence of goaf on surface filling preparation station.The results show that:there are obvious tensile stress in the roof of 18 goafs in 145 goafs,and the displacement is relatively large.If not handled in time,with the increasing of pillar load,it will lead to pillar instability and failure,and eventually lead to a series of ground pressure problem.The research results provide a theoretical basis for the treatment of mined out areas.