基于FLAC^(3D)的分层开采再生顶板裂隙控制效果分析

Analysis on crack control effect of regenerated roof for slicing based on FLAC^(3D)

为了解决顶板裂隙漏风诱发的顶煤甚至采空区遗煤自燃问题,基于州景煤矿再生顶板现场实况,应用FLAC^(3D)软件对比研究有无灌注纳米浆泡材料处理的再生顶板应力、位移以及孔隙率变化。结果表明:在不采取任何控制措施的情况下,巷道顶板位移大,极有可能会发生顶板垮塌事故且应力在两帮集中,两帮位移大,巷道断面收缩率极大;若使用纳米浆泡材料胶结再生的顶板,可以使巷道顶板产生不明显的位移,仅有稍微的下沉,虽然两帮仍有应力集中的区域,但两帮位移极小,巷道基本未发生收缩;依据顶板蠕变与孔隙率之间的关系进行理论推导发现,使用纳米浆泡材料注浆胶结的再生顶板其孔隙率变化幅度小,孔隙演化不显著,有利于提高顶板强度并解决再生顶板裂隙漏风问题,进而避免漏风导致顶煤甚至采空区遗煤自燃。

In order to solve the problem of the spontaneous combustion of roof coal and even residual coal in the goaf caused by the air leakage in the roof cracks,based on the on-site working conditions of the regenerated roof in Zhoujing coal mine,the FLAC^(3D) software was used to compare the stress,displacement and porosity changes of the regenerated roof with or without the infusion of nano-particle foam slurry.The results showed that when without taking any control measures,the roof of roadway had large displacement,the roof collapse accident was very likely to occur,and the stress was concentrated on the two sides.The displacement of the two sides was large,and the shrinkage rate of roadway section was extremely large.If the regenerated roof was cemented by the nano-particle foam slurry,the displacement of the roof of roadway was not obvious with only slight sinking.Although there still existed the stress-concentrated areas on the two sides,the displacement of the two sides was very small,and the roadway basically did not shrink.According to the theoretical derivation of the relationship between the roof creep and porosity,it was found that the regenerated roof with the grouting cementation of nano-particle foam slurry had little change range of porosity,and the pore evolution was not significant,which is beneficial to improve the strength of roof and solve the problem of air leakage in the regenerated roof cracks,thus avoid the air leakage leading to spontaneous combustion of the roof coal or even the residual coal in the goaf.