Analysis Of Stope Stability Of A Layered Gem-jade Mine Considering Friction Effect

The stability of bedding rock stope has been the focus of research in the field of geotechnical engineering.There exists some difference between the research and the actual situation,because the characteristics of the bedding structure are often simplified during the current layered rock mass mechanics analysis.Under the research background of Guizhou layered gemstone mine,Introducing the concept of friction effect,combining the similar simulation test,numerical analysis and reliability calculation together,on the basis of the reliability index,taking into account the effect of friction,depth,and width of pillar stope span with the influence of stope,to study the stability of the stope under different stope parameters and bedding planes.The research results of the dissertation mainly include:(1)According to the similarity principle,it is determined that when the weight ratio of similar material sand: lime: gypsum is 307:82:72,the mixing effect is the best.Similar tests show that the strain along the bedding plane increases with the increase of the friction coefficient,the lateral strain at the edge of the roof increases by 50%,the lateral strain of the pillar increases by 35%,and the strain in the direction of the vertical bedding plane is basically unchanged It is proved that the friction effect has an effect on the stability of the stope.(2)The FLAC3 D was used to further investigate the stability of the stope considering the friction effect.The results show that the horizontal stress of the friction model ore pillar is larger than that of the conventional model,and the difference between the pillar width and the width of the pillar gradually decreases,and the difference at the roof is smaller;the vertical displacement of the friction model is larger than the conventional model,and the difference between the two ends is small.There is a large difference in the center of the roof;the maximum shear stress of the friction model pillar is larger than the conventional model,and the latter is about 95% of the former;when the other conditions are constant,increasing the width of the pillar,reducing the stop span and the depth can improve the mining The stability of the field.(3)Taking the reliability index as the evaluation standard,the stope under different working conditions was compared and analyzed.The research shows that the reliability index of the friction model is generally higher than that of the conventional model;when the reliability index is equal to 1.64,it is the limit state;when the friction effect is considered,when the span of the mine room is 9m,the depths of 50 m,100m,150 m,200m,and 300 m are buried.The width of the next smallest pillar is 3m,4m,6m,7m and 9m respectively,which is less than or equal to the conventional model.When the width of the pillar is 3m,the maximum span of the mine is 9m,8m,7m,5m and 3m in different depths,greater than or equal to the conventional model.