Analysis On Stability Of Surrounding Rocks In Metal Mine Tunnel And Study Of Optimization Of Monitoring Points’ Position

XiaDian Gold Mine belongs to underground mines in which the crustal stress condition iscomplex. It is difficult to predict the wall rock damage and roof collapse after blasting and inlong time working environment. The existed rock fall danger can be distinguished by naked eyeor by beating on the wall rock and the roof. Scientific monitoring approach is lacking. For thesake of underground mine stability and worker safety, it is very necessary to analyze the minetunnel stability, to inspect and alarm the mine safety. So the study in this paper has veryimportant theory and practice values.In this thesis, the research status of underground surrounding rock stability is systemicconcluded and the main research method, existed problems and development direction arepresented. At the same time, the emergence and study status of blasting seismic effect isexplained. The development trend of the blasting seismic effect study and the significance instability analysis of underground surrounding rocks and forecasts of disasters are pointed out.Using the FLAC3Dwhich based on the three dimensions Lagrange analysis method, thearticle researched and discussed the the stability of surrounding rocks in underground mine withdata in site and numerical simulation are researched and discussed in this article.Firstly, the stress, displacement and plastic area change of the underground tunnel afterexcavation are studied, and the affection of nearby tunnel excavation to the surrounding rocksstability is also discussed. Study indicates tension stress appeared around the tunnel after thetunnel is excavated. With other tunnel excavated, the deformation displacement graduallyenlarged. Meanwhile, the change of plastic destroy area is obscure.Secondly, the dynamic characteristics of tunnel under blasting was calculated, and thestress redistribution regularity of the excavated surrounding rocks and the change of thedisplacement were analyzed based on the blasting effect which ascertained theoretically theaffection degree of blasting vibration to the stability of surrounding rocks. Study indicates that after blasting the safety factor of the surrounding rocks near blasting area is decreased, the stressof surrounding rocks is increased, the displacement is reduced, the acceleration and speed isincreased notability and all of these present fluctuation variety with the proceed of blastingseismic wave. To the surrounding rocks induced gap, displacement and change of speedenlarged the gap and the possibility of falling. Blasting seismic waves is detrimental to thestability of the surrounding rocks.Finally, according to the results of numerical simulation, the change order of displacementand acceleration in tunnel before and after the imposed bursting seismic wave arecomprehensively analyzed. The sensor point layout which monitors the displacement andaccelement of surrounding rocks are optimized and a reasonable and economic monitor systemis built which combined regular monitor with long-term monitor, combined regular points withkey points. All of these provide theoretical basis for layout points experiment and reinforcementsurrounding rocks.