Research On The Process Parameters Of The Fully Mechanized Caving And Overlying Strata Movement Under The Conditions Of The Weak Bond Roof And The Thick Coal Seam

Studied the main mining layer6#coal belonging to the west in a coal mine in this paper, The coal seams belonging to the Carboniferous、Upper Permian Series Taiyuan Formation、 The seam has an average thickness of17m, buried depth518m, coal seams buried deeper。Combined with the low strength of the roof strata and the low maturity of roof strata and coupled with the Roof multi argillaceous, calcareous cemented filling。the roof strata Affected by late tectonic stress, forming a fissure-dual porosity media。Therefore, lead to Structure of the low intensity of the roof strata and Poor cementation degree。After rock contact with water softening deformation or even disintegration, The roof is weak bonding of roof。Research Less the process parameters of fully mechanized caving mining and overlying strata movement under circumstances of Such mining depth conditions and weak bond roof case the In the past。In this paper, based on a detailed understanding and analysis of the results of previous studies, use PFC2D, FLAC3D numerical simulation, laboratory similar material simulation and field measurement combining a variety of research methods。In-depth study the law of parameters of fully mechanized caving mining and overlying strata movement。Analyzes different the mining and caving ratio impact of Top coal mining rate and the different caving step distance and caving manner impact of Top coal mining rate Under the conditions of the same mining and caving ratio, Select a reasonable mining and caving ratio、 Caving step distance and caving method。Studied the process、changes and characteristics of the overburden movement after coal seam mining and Explore the overburden movement law。The results show that whit the once mined coal seam thickness increases, the direct top cross-backward will not be full of mined-out area。Lead to break down to continue to move upwards, until the formation of a stable structure。On the basis of PFC2D numerical simulate the mining and caving ratio, through the FLAC3D numerical software established a stope stress field numerical simulation model。Studied the floor strata vertical stress distribution, horizontal stress distribution、shear stress distribution and formation of plastic zone distributionof of overlying strata。The conclusion is backplane supporting peak pressure basically in15m in front of working face, maximum horizontal stress close to2m～8m at the front of the bottom wall coal, shear failure of the top coal front of the coal wall70m working face the range of shear failure is Farther closer the roof。Combined with analysis results of top coal caving technology, through FLAC3D numerical simulation software, simulated the Hydraulic support of working face under the condition of seam of fully mechanized caving、mechanized mining height of5.0m、caving height12m and Caving step distance of1.6m。The conclusion is that the largest hydraulic support working resistance is13692KN under the condition of Working width is200m。...