双层采空区重叠率对隔离顶柱稳定性影响分析及其力学模型

Study on influence of overlapping rate of double layer gobs on stability of isolation roof and its mechanical model

目前房柱法仍是金属矿山主要的开采方法之一,由于采空区处理得不及时,往往形成大量的双层采空区,此时,隔离顶柱的稳定性及重叠率是影响采空区稳定性的主要因素。考虑不同重叠方式的双层采空区应力传递的不同,基于弹塑性理论,建立双层采空区重叠隔离顶柱的二维固支梁简化力学模型,并以石人沟铁矿为工程案例,分析重叠率对隔离顶柱稳定性的影响规律。结果表明,双层采空区的不完全重叠造成地下应力传递的变化,使隔离顶柱不同区域的受力明显不同,从而造成内部应力及位移的突变,随着重叠率的增加,突变的程度越大,最终非重叠区域远远大于重叠区域,因此实际工程中要重点关注该区域的稳定性。

Currently, the room and pillar method is still one of popular mining methods in metal mines. The gob disposal is not timely and this would result in the appearance of double layer gobs. The stability of isolation roof and the overlapping rate of double layer gobs are the main influence factors of stability of gob. Considering the stress transmission of different overlapping rate of double layer gobs and based on the elastoplastic theory, this paper establishes a simplified two-dimensional mechanical model of isolation roof of double layer gobs. Taking the Shirengou iron mine as an engineering example, it is an- alyzed that the influence of overlapping rate on the stability of isolation roof. The results show that the partly overlap causes the change of stress transmission and the stress on different parts of the isolation roof is different. Therefore, the stress and displacement appear mutation in the transition region between the overlapping area and the stagger area. The greater overlap ratio is, the greater the degree of mutation is. The stress and displacement of staggered part are bigger than the overlapping part which should be paid particular attentions.