Study on deformation response features and instability mechanism of complex roof dynamic roadway

In order to explain the serious floor heave, support failure and other mine strata pressure phenomenon occurred mechanism of the mine roadway with the complex roof, the surrounding rock bed separation monitoring, numerical simulation and other method were comprehensively applied to study the bed separation deform ation and support instability features of the mine roadway. The elastic strain energy of the coal pillar core area were compared under the different status to reveal the d eformation instability mechanism of the mine dynamic roadway. The study showed that under the dynamic influences,a large bed separation was occurred in the surrou nding rock with a range of 2-5 m, the roof bed separation value would be 109 mm in max and 62 mm in average. The bed separation value of the sidewall along the co al pillar would be 130 mm in max and 82 mm in average. The strain energy of the elastic core area in the coal pillar was higher than the non dynamic roadway and the e nergy concentration coefficient of each cross section could be 18.6,16.9,12.6,8.0 and 5.1 individually. The above site measurement and the simulation analysis revealedthe instability mechanism of the trial roadway from the deformation response of the roadway, the energy accumulation of the coal pillar and other aspects. Thus under th e double influences of the advance support pressure and the thick and hard main roof broken in the goaf, the bed separation of the roadway and the elastic energy conc entration degree of the coal pillar would be enhanced, thus the roof beam, leg and other structure parts of the H steel support were hard to meet the support requirement sof the mine roadway and the above mine dynamic pressure phenomenon was occurred.