已关闭矿井老采空区稳定性评价方案研究

Study on stability evaluation scheme of old goaf in closed mine

为分析某已关闭矿井的老采空区稳定性,通过对矿山采空区现状的详细调查,明确采空区状态特征,采用定性分析和数值模拟方法进行评价。研究结果表明:-250 m中段以上采空区形成已有20余年,覆岩厚大、完整性好、强度高且地表无开裂下沉,综合判断其处于稳定状态;-250 m以下中段采空区形成后,出现局部区域的应力集中,最大拉应力约1.5 MPa,未超过岩层的抗拉强度;最大竖直位移出现在顶板位置,整体位移变形较小,下沉和底鼓现象不明显;地表覆土后,采空区应力和位移几乎无变化,综合分析来看,井下老采空区可以保持稳定。研究成果可以为老采空区稳定性的分析提供技术路线。

In order to analyze the stability of the old goaf in a closed mine,through the detailed investigation of the current situation of the mine goaf,the characteristics of the goaf state are clarified,and the qualitative analysis and numerical simulation methods are used to evaluate.The results show that the goaf above the middle section of−250 m has been formed for more than 20 years.The overburden is thick,complete,strong and has no cracking and sinking on the surface.It is in a stable state.After the formation of the middle goaf below−250 m,the stress concentration in the local area occurs,and the maximum tensile stress is about 1.5 MPa,which does not exceed the tensile strength of the rock layer.The maximum vertical displacement occurs in the roof position,the overall displacement deformation is small,the sinking and floor heave phenomenon is not obvious.After the surface is covered with soil,the stress and displacement of the goaf are almost unchanged.By the comprehensive analysis,underground goaf can remain stable.The research results are expected to provide a technical route for the analysis of the stability of the old goaf.