Study on classification and support of surrounding rock of mining roadway in extremely close coal seams

Inordertoexplorethestabilitycategoryandsupportmodeofsurroundingrockof mining roadwayinextremelyclosecoalseams,thestabilitycategoryofsurroundingrockisdeterminedbycomprehensiveevaluationwithmathematicalmethod.Firstly,themathematicalmodelisestablishedbyusing themethodoffuzzycomprehensiveevaluation,andfactorssuchasthenatureofsurroundingrockand stress environment are selected as the classification index of surrounding rock.Then, fuzzy comprehensive discriminant matrix,index weight and membership degree of surrounding rock are solved.Then,theclassificationofsurroundingrockstabilityisverifiedbythemethodofgreycorrelation degreeanalysis.Finally,thecorrespondingroadwaysupportmodeisputforward.Theresultsshowthat degreesofmembershipofminingroadwayinextremelyclosecoalseamstoⅠ-Ⅴtypesurrounding rocksare0.1846,0.2117,0.1866,0.1776and0.2394,respectively.Thedegreeofmembershipof Vtypesurroundingrockisthelargest,whichisconsistentwiththeverificationresults.Surroundingrock belongstoVtypeextremelyunstablesurroundingrock.Inaddition,theroofisbrokenandroadwaypressureissmallduetoextremelyclosemining.ThenU-shapedsteelbeamshedsupportisproposed.The observationofrockpressureshowsthattheeffectofroadwaysupportisremarkable.