Research On Water Injection Top-coal Crushing Rule And Application In Steep Thick Coal Seam

This paper, referring to mining technological characteristics of top-slicing system ofsublevel caving at Jian-gou coal mine’s steep thick coal seam, obtains the regulation ofmechanics parameters and the coal petrography failure criterion in different moisture contentcases through the general theoretical analysis of top-coal failure and laboratory mechanicsexperiment. It simulates top-coal damage evolution process of different hole pattern byFLAC^3Dwhen water injection or not, at the same time, it also discusses the thick top-coalcrushing rule under the condition of water injection to direct top-coal water injection inproduction.First of all, it uses sublevel model to study the effect of roof and floor on top coal intop-slicing system of sublevel caving at steep thick coal seam and studies the top-coalbreaking and caving rules. It also studies the relationship between coal rock mechanicsparameters and moisture content through the mechanics experiment and sets up coal failurecriterion under the different moisture content.Secondly, it sets up a corresponding stress estimation model and a fine water injectionmodel through the geological material of Jian-gou coal seam by FLAC^3Dto simulate stressfield and displacement field and plastic zone when coal is caving in the condition of waterinjection or not and different hole pattern. This paper analyzes the distribution rules of stressfield and displacement field and the evolution process of plastic area in the condition of waterinjection or not and different hole pattern, and the top-coal failure factors in differentcircumstances. It is also obtains the destruction and migration regularity of top-coal under thecondition of water injection and the distribution of key softening area.Finally, using the results of the study, the water injection work is put into practice infully-mechanized sublevel caving mining working face of Jian-gou coal mine. Practice hasproved that after water injection the recovery rate increased, the raw coal productionincreased, face dust capacity greatly reduced, and the effect of water injection is good.