复杂条件下露天转地下开采断层对采空区影响研究

Study on Fault's Influence to Goaf in Underground Mining Transferring from Open-Pit in Complex Situation

针对铜绿山Ⅰ号矿体露天转地下开采的复杂情况,采用FLAC3D分析矿体上盘断层破碎带对采空区的影响,以指导现场施工。分别建立有断层模型和无断层模型,对2模型采用同一种开挖方式：布置1#采场及2#采场,2采场之间留下隔离立柱用于支撑顶板。从压应力及位移量2方面比较2个模型的开挖结果,研究表明,断层使采矿作业条件恶化,主要表现在2个方面：①断层降低了矿体上盘岩体的整体性和连续性,使采场两帮压应力增大0.01～0.45 MPa;②顶柱厚度较大时,断层对1#采场几乎不产生影响,对2#采场影响较大,导致其顶板下沉量增大,表现为2#采场顶板绕立柱顶部旋转;当顶柱厚度h≤16 m时,断层对2个采场均产生影响,均导致其顶板下沉量明显增大,表现为2采场顶板绕1#采场左帮顶部旋转。

For the complex situation of Tonglvshan No.1 orebody in underground mining transferring from open-pit,influence of fault in hanging rock was analyzed by FLAC3D,in order to guide on-site construction.One model with fault and another model without fault were established respectively.Two models took the same form of excavation：stope 1 and stope 2,leaving column between two stopes in order to support the roofs.The results of excavation by both of methods are compared through stress and displacement,and the research indicates that the fault makes the situation of mining worse, mainly showing two aspects： （1）fault weakens the integrity and continuity of hanging rock, and makes the compressive stress on stope- boundary increase by 0. 01 - 0.45 MPa;（2）when the thickness of pillar is large, fault seldom influences stope 1, but makes large influence to stope 2, causing the increasing subsidence of the roof, and showing that the roof of stope 2 rotates around the top of the column. When the thickness of pillar h ≤ 16 m,fault makes influence to both of stopes,leading to their roofs displacement increase conspicuously, and showing that both of stopes＇roofs rotate around the top of left-boundary in stope 1.