Room-and-Pillar Stress, Deformation And Reasonable Structure Parameters In Special Surrounding Rock

Room-and-pillar method has many advantages such as short well construction period,less investment, suitable to complicated geological conditions and so on. It’s structureparameters research is a very important subject，the unreasonable structural parameterswill lead to the unstability problem of stope. There are many studies on the stress,deformation and structure parameters in the coal，gypsum mine and other conventionalore，but we have no experience on the special rock ore.This paper based on a special ore mining project，thorough researched the stress anddeformation of bord and pillar with the theory of broken rock zone and the view ofpressure arch. Reasonable structure parameters is proposed and the main research contentsare as follows:(1) Through the numerical simulation, analysis the stress and deformation of bordand pillar when mining, the excavation only affect the stability of the same row of bordand pillars, and the stability of middle bord and pillar is the worst.(2) By orthogonal test, analysis the influence of the buried depth, bord width, bordheight and bord length on the stability of bord and pillar. We get the conclusion that bordroof subsidence is related with four factors, broken rock zone thickness mainly depends onbord width, and pillar vertical stress concentration factor mainly depends on bord heightand width, and get the regression function of the influence factors.(3) Through the theory of broken rock zone and pillar failure mechanism, analysis thevariation of broken rock zone thickness and pillar vertical stress concentration by differentpillar size, the reasonable pillar size are7m and6m. Then, analysis the effect on stopestability from bord numbers, we can know the change of bord number mainly affect thestability of pillar.(4) Further, analysis the stress and deformation law of double bord and pillar, we canknow the reasonable interlayer thickness are8m,10m,14m for different pillar overlappingrate. The pillar overlapping rate higher mined-out area more stable. Then, analysis thestress and deformation law for layers of bord and pillar, wen can know the stability ofbottom bord and pillar is the worst.(5) Put forward reasonable structure parameters for a special ore according to theresearch conclusions.