Experimental study on stability characteristics of cement-based slurry for coal seam floor grouting
In order to study the stability and water separation change law of cement-based slurries,slurry ratio tests were conducted un-der different water solid ratios and fly ash content conditions.The slurry characteristics,final water separation time,and water separation thickness were obtained,and the influence of temperature on slurry stability and mechanical strength characteristics of slurries with dif-ferent stabilities were analyzed.The growth curve of slurry water separation thickness was drawn,and the slurry stability and dynamic change law of water separation were elucidated.The results showed that the water solid ratio was the main factor affecting the stability of the slurry.As the water solid ratio decreased from 3∶1 to 1∶1,the water separation time of the slurry was extended by 40％to 62％,and the stability of the slurry was significantly enhanced.The performance parameters of the slurry slowly changed with the change of solid phase ratio.The addition of fly ash prolonged the water precipitation time by 1.72％to 17％,improved the viscosity,stone content,and stability of the slurry,but significantly reduced its mechanical strength.The increase in temperature promoted the water separation process of the slurry,but the stability of the slurry slightly decreased.The water separation rate of the slurry showed a semi"C"shaped time-varying characteristic of rapid growth in the early stage,slowing down in the middle stage,and stabilizing in the later stage.Engi-neering practice shows that dynamically adjusting the slurry ratio during the grouting process can improve the stability of the slurry,en-hance the injectability of the formation,reduce the risk of water inrush in the working face,and provide technical reference for the grou-ting treatment project of the coal seam floor.
floor groutingcement-based slurryslurry ratioslurry stabilitywater separation process
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