| There are many researches on overlying strata removing law of fully mechanized caving face under the deep well and shallow coal seam with thin bedrock, but it is seldom that under deep well thick alluvium and thin bedrock. Based on this situation, this paper proposed the research on overlying strata removing law of thin bedrock fully-mechanized workface under deep well thick alluvium.This paper studies about the 3 coal and its deposit geology condition of Xinjulong Company,3 coal buried deep, bedrock thin, and rick good water, considering its occurrence condition, think 3 coal as the typical buried thick alluvium occurrence condition, and decorate a form of working face roadway and mining technique were reviewed in this paper.Secondly, it analyzed the form of roof strata, researched loads distribution law of the key strata by key strata theory and force analysis of key strata, theoretically analyzed first Fracture step distance and periodic Fracture step distance, and derived the computational formula of fracture step distance.Instability of key strata mainly includes sliding instability and rotary instability, through theoretical analysis of abnormal pressure mechanism of fully mechanized caving face, reach that the key reason of abnormal pressure is sliding instability of key strata and propose type-selection design of fully mechanized mining support.Then, this paper performed simulation of removing evolution rule of shallow coal seam with thin bedrock by numerical simulation, by this simulation confirmed that the overlying strata removing scope is 141m, combined with mine pressure observation results, and obtained that ZF11000/38/20 fully mechanized mining support is more adapted to face production.Finally, this paper analyzed the reasons of supports crushing accident in production and proposed accordingly precautionary measure and overlying strata control technique of normal production in working face to guarantee safety production of working face. |
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