INTACT-LOOSE MEDIUM EQUIVALENT TRANSFORMATION AFTER COUPLED CRACKING AND ASSESSMENT OF CAVING CAPABILITY
CUI Feng1，2，LAI Xingping1，2，CAO Jiantao1，2，SHAN Pengfei1，2
(1. School of Energy，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China；2. Key Laboratory of Western Mines and Hazard Prevention of Ministry of Education，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China)
Abstract：A discrete element model(DEM) of describing the equivalent strength of coal mass after cracking due to the coupled action was established for the quantitative evaluation of the effect of cracking due to coupled action. The overall strength was taken as an index to achieve the equivalent transformation of discretization of intact to loose coal mass. The caving of the top coal and the flow pattern were researched with DEM. The hinge relationship of discrete particles and its influence to caving after coupled cracking were analyzed. The relationship between the caving and flowing capacity of coal mass，the parameters of explosive load and the injecting pressure of water was quantified and the result was verified in an engineering practice. The essence of coupled cracking was the spreading of the gas and blast wave generated in the explosion in the softened coal-rock. The overall strength of coal-mass was regarded as an equivalent conversion index for the equivalent transformation between the different algorithms for coal-mass. The method of coupled cracking increased the caving effect of coal-mass by reducing the tensile stress of blocks and the amount of contact between particles. The strength of coal mass for fully caving and the peak strength meeting the requirements of recovery ratio for the thick coal seam were obtained. The quantitative assessment of coupled cracking in coal mass under the complex environment was accomplished.
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2015, Vol. 34 
