Critical failure time of roof and standing pillars in China western mining area
Abstract：Stress and displacement field of roof and standing pillars (RSP) are always in a state of flux,its stability should be studied before recovering the standing pillars.The creep process of coal pillars is analyzed by Flac3D.The process could be divided into three stages:rapid deformation,slow deformation and accelerating failure.Also,the laws of plastic zone and inner stress distribution pattern of coal pillars at different stages are obtained.Based on the theoretical analysis,one thin plate on elastic found model is established to analyze the relationship between the roof deformation,the force on the pillars and the ranges of plastic zones of coal pillars,and the proposed model allows to reveal the dynamic evolution of the decreasing-failure process of RSP.Furthermore,a criterion for evaluating the critical failure time of RSP is then given in this study,which is illustrated through an engineering case.
Keywords：roof and standing pillarsinner stress distribution patternone thin plate on plastic found modelranges of plastic zones of coal pillarscritical failure time
Publication Date：2017-01-01
Pages：7( 397-403 )