煤矿采空区充填高浓度胶结材料流变特性试验研究

Experimental study on rheological properties of high concentration cementing materials in coal mine goaf filling

为保证高浓度胶结材料顺利输送到采空区,并控制其堆积效果,选取水泥和粉煤灰为胶结材料,风积砂为骨料,对不同胶结材料配比下高浓度充填浆液流变特性的影响规律进行研究。结果表明:浆液浓度82%,胶骨比1∶5时,浆液的剪切应力、黏度和触变性随粉煤灰占比增大而减小。浆液浓度82%,胶结材料中水泥和粉煤灰比1∶3时,浆液的剪切应力和黏度均较小,触变性随浆体中骨料占比的减小而减小。胶骨比1∶3,胶结材料中水泥和粉煤灰比1∶3时,浆液的剪切应力、黏度和触变性随浆体浓度减小而减小。流动性好且触变性小的浆液材料有利于高浓度充填浆液泵送,即所选浆液需浓度和胶骨比相对较小,粉煤灰含量相对较大,此时浆液的剪切应力和黏度均较小,浆液的流动性较好,触变性较差。

In order to ensure the smooth transportation of high concentration filling slurry and the effect of accumulation in goaf,this paper makes a preliminary study of the effects of cement and fly ash as cementitious materials and aeolian sand as aggregates on the rheological properties of high concentration filling slurry under a series of samples with different gelling materials ratio.Test results show that,when the concentration and proportion of cemented material and aggregate are constant,the shear stress,viscosity and thixotropy of the slurry decrease with the proportion of fly ash increases.When the concentration and the content of cement and fly ash in the cementitious material are constant,the shear stress,viscosity and thixotropy of the slurry decrease with the proportion of aggregate decreases.When the proportion of cemented material and aggregate and the content of cement and fly ash in the cementitious material are constant,the shear stress,viscosity and thixotropy of the slurry decrease with the concentration of slurry decreases.Good fluidity and good thixotropy of the slurry material is conducive to slurry pumping.That is,the concentration of selected slurry and the proportion of cemented material and aggregate should be relatively small,and fly ash content in slurry should be relatively large.At this point,shear stress and viscosity of the slurry are small. The fluidity of the slurry is better,and thixotropy of the slurry is poor.