Study On The Motion Rule Of The Overlying Strata After The Whole Grouting Reinforcement Of Efflorescent Oxygenized Belts

Gubei Mine 1512(3) working face overburden efflorescent oxygenized belts with rock broken mud can not form a bearing structure. The bearing stratum is only 18～25.8 meters. In order to avoid the occurrence of the work surface pressure frame collapse. Grouting reinforcement of the roof of the efflorescent oxygenized belts from the ground construction. Build a layer of artificial bearing layer. Load transfer from the upper alluvium layer. This paper uses the theoretical analysis,Numerical simulation. Study on the movement law of overlying strata before and after the integral reinforcement of the efflorescent oxygenized belts. The main research contents include: Fracture characteristics of overburden strata in mining field. Distribution law of supporting pressure of working face,Mining subsidence law.Development of overlying rock fracture,Support working resistance. Based on the working resistance of the support after the grouting in thick loose layer efflorescent oxygenized belts, Analysis of measured data of surrounding rock of roadway, Study on the adaptability of 1512 (3) mining field hydraulic support.(1)After grouting in the efflorescent oxygenized belts,the compression deformation of the arch thrust line of weathered bedrock is obviously smaller,The height variation of the weathered bedrock is also reduced. The total subsidence of weathered rock thin plate decreases.The bond strength of the fracture surface is improved by the bond of the slurry,Cohesion increases. The RQD value of the rock mass index of the wind oxidation zone after grouting is greater than 70%, Uniaxial compressive strength increased to 15MPa, Tensile strength is not less than 3MPa, The apparent surface of rock mass after grouting reinforcement is relatively flat and smooth.(2) After the whole grouting of the efflorescent oxygenized belts in the working face of the thick unconsolidated layers. The stress peak value the stress concentration factor, the vertical stress range and the maximum vertical displacement in the middle of the goaf are significantly reduced. The fracture development zone decreases in the weathered bedrock after grouting, For the first time,the increase of the pressure and the peak value of the support pressure and the distance between the support pressure and the coal wall are decreased.(3)After the whole grouting of the efflorescent oxygenized belts in the working face of the thick unconsolidated layers,Each part of the working face of first Weighting Interval of Main Roof from 27.7 to 36.5m,average 31.49m, dynamic load factor of 1.34～1.42. The middle of the mining field to the pressure step is smaller, to press frequently, the upper and lower head side to the pressure step distance is bigger. The first stope pressure, after the head began to pressure,finally end pressure machine, presents the segmented pressure phenomenon. Mining field has experienced three major cycles to pressure. Different parts of the working face of the old top cycle to press the step distance from 9.9 to 17.9m,average 13.76m. In the middle of the working face, the working resistance of the support is generally larger, The level of the main roof rock is grade ii,The Pressure of main roof show obviously.(4)The supporting frame can meet the requirement of roof control in the period of first weighting and periodic weighting.in the front of the coal wall 10 meters by mining is very significant. In the range of 20m, the influence of the mining area is obvious, Outside the 30m affected by mining gradually weakened, Outside the 80m is basically not affected by mining.