The mechanism of rockburst in district coal pillar with high deviatoric stress and mining tremors impact and its prevention methods
WANG Hao
ZHAO Yixin
MU Zonglong
JIAO Zhenhua
ZHANG Xu
LU Zhiguo
Abstract：The mechanism of rockburst during mining was analyzed on the base of deviatoric stress,equivalent stress,Mises criterion and energy balance theory.Additionally,the overlying strata movement,deviatoric stress and mining induced tremor activity in relate to active mining,as well as the rockburst prevention methods,were studied with the geological condition of Zhangshuanglou coal mine.The results show that two criteria should be satisfied for causing rockburst,firstly the overlap deviatoric stress caused by gob and tremors surpasses the strength of coal,secondly the overall energy release ratio of elastic energy cumulated in coal and dynamic energy induced by tremors surpasses the energy consume ratio of steady fracturing.As the excavation processing,the overlying strata would break and form T-shape structure around the district coal pillar.Taking the second invariant of deviatoric stress (J2) to represent the deviatoric stress (σ'ij),it is noticed that σ'ij has a M-shape over the coal pillar and transfers to n-shape as the mining procesing,which means the plastic fracture zone is extending to inner pillar zone.The dynamic stress was analyzed in terms of seism frequency,energy and seismic focus,it is found that the majority of tremors have low energy and their focus gathered in mining zone and district coal pillar zone.Accordingly,several methods are proposed to prevent rockburst,such as overlying strata bursting,extending the width of coal pillar,overlying strata mining and large stress-relief borehole.
Keywords：district coal pillarrockburstmining tremorsdeviatoric stressoverlying strata structure
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 1202-1210 )