| There are many difficult problems in fully-mechanized top coal caving with steeplyinclined coal seam for its particularity occurrence, one of them is the support stability offully-mechanized caving face. Hydraulic supports are the major equipment infully-mechanized caving face, the working conditions have a direct influence on safety andproduction of face. During the coal production, once a support toppling, it will cause theadjacent supports. In severe cases, a large number of supports up and down from the initiallyinstable support will lose stability, resulting in the stability of the face cannot run normallyand conditioning safety production. Thus, study the cause of the hydraulic support toppling offully-mechanized caving face with steeply inclined thick coal seam and to identify appropriatecountermeasures in-depth analysis has a very important significance to ensure safe productionand high efficient.This paper integrated use of theoretical analysis, field research, similar simulationexperiments study and field trials, study for the cause of No.1121unstable three soft coalseam fully-mechanized caving face hydraulic support toppling and re-stabilization technologyin Changshanzi Coal Mine of YaoJie Coal Electricity Group Co., Ltd. Through the study, theinfluencing factors of support stability includes geological conditions of face, itself features ofhydraulic support, surrounding strata nature, coal mining technology and management factor.The cause of hydraulic supports toppling is that the height of open-off cut taller than themaximum height of the support. During the mining process, prematurely coal caving andleakage of the top coal between adjacent supports forward canopy result in the canopy ofhydraulic support cannot compacting contacts with roof (coal), bring the canopy of hydraulicsupport force unequally and then the hydraulic support force unequally. At the same time, because the support itself fails and the workers operate unskilled or mistakes leading to thesupport crowed, tipping and biting. By establishing the model of hydraulic support force,analyze the anti-tipping stability, anti-sliding stability and empennage anti-downswingstability of hydraulic support in the fully-mechanized caving face with steeply inclined coalseam. And on this basis study the technology to control the stability of hydraulic support.Comprehensive field research and theoretical analysis, study the causes and mechanism ofhydraulic support toppling of No.1121fully-mechanized caving face in Changshanzi CoalMine, then determine the "safeguard-right-advance-stabilize" technology for right thetoppling hydraulic powered support dynamically that gradual cutting coal wall and rightinghydraulic powered support from above down time after time for the support into coal wall, toensure that prospective support station, live station, station stable. The field experiments showthat the technology achieved good effect.The results of this study have directive significance for fully-mechanized top coal cavingface of steeply inclined seam to enhance supports stability and prevent hydraulic poweredsupports toppling. And the re-stabilization technology for toppling hydraulic poweredsupports in this paper can provide reference for the similar conditions face to manage afterhydraulic powered supports toppling. |
