深部大规模开采岩体稳定性数值模拟研究

基于FLAC3D对马城铁矿深部大采场开采及回填过程中,围岩与充填体的稳定性进行数值模拟计算,并通过现场工程试验进行了验证。研究结果表明:(1)一步回采后,矿房出现顶板下沉和底鼓现象,间柱顶底板处应力集中明显,最大应力达到36.45 MPa,围岩局部呈塑性破坏;二步回采时,矿柱位置应力集中加剧,最大集中应力达到69.35 MPa,顶板最大位移15.01 cm,空区部分围岩呈失稳状态。(2)一步回采胶结充填后,胶结充填体对空区围岩起到了支撑作用,在一定程度上恢复了围岩三向受力状态,矿房顶底板应力集中程度减弱;二步回采尾砂充填后,充填体进一步抑制了空区塑性区的发展,围岩受力分布相对均匀,顶板位移与之前相比基本不变,顶底板变形得到了有效控制,保证了深部大采场开采的安全性和可靠性。

Numerical Simulation Analysis on Stability of Deep Large-scale Mining Rock Mass

Based on the process of deep stope mining and backfilling with FLAC3D in Macheng iron ore,numerical simulation on the stability of surrounding rock and filling body is made,and field tests were carried out to validate the simulation.The results showed:①After one step stoping,The roof of the mine has been subsiding and distressing,and the stress obviously concentrates at the top floor with the maximum stress of 36.45 MPa,and local plastic damage of surrounding rock;At the two-step stoping,the stress concentration of the ore column increased,with the maximum concentration stress reached 69.35 MPa,and the maximum displacement of the top plate 15.01 cm,resulting that the surrounding rock in the empty area was unstable.②After the step of cementation filling,cementing filling body has played a supporting role in surrounding rock,and restored the triaxial stress state of surrounding rock to a certain extent,and lowered stress concentration degree in mining roof;After two-step stoping backfilling,filling body can further inhibit the mined-out development of plastic zone,and the stress distribution of surrounding rock is relatively uniform,and roof displacement does not occur.Roof and floor deformation have been effectively controlled,and the safety and reliability of the deep large-scale mining area are guaranteed.