| As one of "green mining" technology of waste gypsum filling, can effectively solvethe problem of the bad environment of coal mine, is an ideal way;As the country’sincreasing demand for coal, coal resources reserves dwindling,"three under" pressure isan urgent need to solve the problem of coal, gangue gypsum filling mining caneffectively solve the problem, and has made some achievements, on this basis, in thispaper, the physical and mechanical properties of the paste filling body for furtherresearch.As a core component of gypsum filling mining technology of coal and gangue,the study of filling materials become a top priority.Can be used as a medium of pastefilling material has a lot of, in this paper, we study mainly USES the coal gangue,cement, fly ash and additive, early strength agent and water as raw materials.Paste filling slurry pumpability is can reflect the paste slurry pump of a compositeindicator, embodied in paste slurry by bending parts and taper pipe and pipe fittingability, is the paste filling slurry stability and plasticity and liquidity in the pumpingprocess.Slurry slump, extension and bleeding rate of such indicators can be accuratelyreflected the slurry pump performance good.Slurry slump should not be less than180mm, but around200mm is more appropriate.The bleeding rate of the slurry should beless than3%.By laboratory studies have found that in other factors under the sameconditions, slurry slump decreases with the increase of the rate of coal gangue finebottles, slow decrease with the increase of adding amount of cement, with the increaseof the dosage of fly ash is increased after decreases, and decreases with the increase ofmass concentration of slurry, with early strength agent decreases with the increase ofadding amount;Slurry extension degree decreases with the increase of the rate of coalgangue fine bottles, slow decrease with the increase of adding amount of cement, withthe increase of the dosage of fly ash is increased after decreases, and decreases with theincrease of mass concentration of slurry, with early strength agent decreases with theincrease of adding amount;Slurry exudation rate decreases with the increase of the rateof coal gangue fine bottles, slow decrease with the increase of adding amount of cement,decreases with the increase of the dosage of fly ash, and decrease with the increase ofmass concentration of slurry, with early strength agent decreases with the increase ofadding amount. In engineering practice, for underground filling mining sequence is first fillingafter coal mining, only paste filling body have a certain strength to continue to coalmining, otherwise unable to control of overlying strata subsidence and fracture, bringsto the production of unsafe factors, influence the working face advancing speed,therefore, early strength of paste filling body should have enough;After completion offilling, filling by overburden compressed for a long time, in order not to make thesurface subsidence, damage to the surface topography, filling body in addition towithstand the weight of overburden stress, but also inherit the old roof deformationstress, therefore, late paste filling body shall also have the enough strength.Inexperimental study found: in other influencing factors, specimen curing ages under thesame conditions, the same paste specimen uniaxial compressive strength first increaseswith the increase of the rate of coal gangue fine bottles after slowly reduced, and thefine rate at about45%of coal and gangue, specimen strength maximum;With theincrease of the dosage of cement and increase slowly;Increases with the increase of thedosage of fly ash;Along with the paste slurry quality increase with the increase of theconcentration;With the increase of the dosage of early strength agent. |
PDF Full Text Request