Study On Failure Characteristics And Grouting Reinforcement Of Floor On Close Confined Water

Aiming at solving floor water inrush,floor grouting measurement is adopted to reduce the floor failure zone and block water diversion channel,which effectively prevent floor water inrush accidents.To master the floor failure characteristic,determine reasonable grouting parameters,the thesis adopts theoretical analysis,numerial simulation and field measurement to study the floor failure characteristics,grouting reinforcement mechanism and slurry diffusion law,and achieves the following results:(1)The mining stress and floor failure depth within the working face on close confined water are studied.Based on the semi-infinite plane mechanical model,the expressions of stress components of the floor are constructed and ploted by MATLAB.Based on the slipping line field theory,the expressions of the maximum depth of floor failure zone are constructed.Cauculated by thereotical analysis,this value is 25.52 m in No.2517 working face.(2)The reinforcement effect of floor grouting on close confined water was analyzed.By FLAC3 D numerical simulation,the plastic zone development within floor before and after floor grouting were compared.Floor grouting reduced the depth of floor failure zone to 10 m,which effectively reduced the water inrush coefficient from 0.288MPa/m to 0.06MPa/m.(3)Diffusion law of floor grouting slurry in confined water was revealed.By COMSOL Multiphysics,the diffusion range and grouting pressure of slurry in hydrostatic and hydrodynamic flow fields were studied.Affected by water velocity,the slurry diffusion pattern in hydrodynamic flow field increased from 7.1m to 15 m,and the grouting pressure increased from 6.45 MPa to 7.36 MPa.(4)The engineering practice of floor grouting on close confined water is constructed.The floor grouting desion of 2517 working face in Chensilou Coal Mine has been adopted.After grouting,the water-rich areas of floor reduced from 14 to 3,and the proportion of water-producing boreholes reduced from 71.85% to 15.15%,which achieved success and ensured the mining safety in working face.