| The lower part of coal seams in Shenfu mining area,Shaanxi Province,contain soft mudstone interlayer.When the mudstone interlayer was damped or softened after encountering water,the coal body at the ribs of gateroads appeared slide along the direction of the mudstone interlayer,which seriously threatened the safety of gateroad and mine.In this paper,the research method of field observation,numerical simulation and theoretical analysis was used to study the law of strata behaviors of coal gateroad with soft interlayer,shear slide mechanism of coal gateroad with soft interlayer,and shear slide control technology for surrounding rock of coal gteraoad with soft interlayer.The main research results are as follows:(1)Convergence of gateroads,bolt(cable)force,vertical stress of surrounding rock and failure zone distributions were monitored in the gateroads of 85207 working face,sandaogou coal mine.Mine pressure behavour and and deformation characteristics of coal gateroad with soft mudstone interlayer were obtained in the stages of gateroad tunneling,adjacent working face retreating and next working face retreating.(2)FLAC 3D was used to simulate the mining and geological conditions of 85207 working face,and the influence law of mudstone interlayer on the surrounding rock stress and distribution of elastic-plastic zone were obtained.(3)The mechanical models of surrounding rock of coal gateroad with soft mudstone interlayer in the stages of gateroad tunneling,adjacent working face retreating and next working face retreating were respectively established for mechanical analysis.The slide mechanism of coal rib of gateroad was expounded.(4)It is proposed to control shear slide of surrounding rock of coal gateroad with soft interlayer by such techniques as breaking immediate roof and main roof,optimization chain pillar width and reasonable support parameters of gateroad.(5)According to shear slide mechanism of surrounding rock of coal gateroad with soft interlayer,breaking immediate roof and main roof of adjacent working face was used to reduce slide of pillar rib of tailgate of next working face,and the construction plan was described in detail.(6)The mechanical model of chain pillar with soft interlayer was established and the relation between chain pillar width and slide of pillar rib of tailgate was expounded.The plastic zone distribution of chain pillar with soft interlayer was analyzed,and the stability condition and minimum width of chain pillar were given.The supporting parameters of bolt of coal gateroad with soft interlayer was designed(7)The engineering test of gateroads of 85212 face showed that the shear slide control technology of surrounding rock of coal gateroad with soft interlayer had positive effect. |
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