尾砂胶结充填料浆剪切触变实验及其基于量纲分析的触变性预测模型

Experiment of shear thixotropy of cemented tailings filling slurry and its prediction model based on dimensional analysis

采用桨式流变仪研究了不同质量浓度、灰砂比充填料浆在剪切条件下的触变行为,借助量纲齐次性原理,推导并提出了基于量纲分析的触变性预测模型。结果表明:浓度不同的料浆在触变形态上有差异,高浓度料浆剪切应力的波动性更强;触变性与质量浓度和灰砂比均呈非线性正相关,且水泥比尾砂更能引发触变;剪切过程中,表观黏度先急速下降,然后维持平稳,最后急剧上升,但结束瞬间的最终值小于初始值;质量浓度为64%的料浆剪切应力在剪切速率转折点前呈不规则“U”字型,其他组剪切应力基本以剪切速率转折点为中心左右对称。设计实验对预测模型进行验证,结果显示平均误差率为6.2%,且适应性良好。

The thixotropic behavior of filling slurry with different concentration and cement-sand ratio was studied by paddle rheometer.The thixotropy prediction model based on dimensional analysis was proposed.The results show that the thixotropic morphologies of slurry with different concentration are different,and the shear stress of slurry with high concentration is more fluctuating.The thixotropy is positively correlated with concentration and cement-sand ratio,and the cement can induce thixotropy more than tailings.During the shear process,the apparent viscosity first decreases rapidly,then maintains stable,and finally rises sharply,but the final value is less than the initial value.The shear stress of the slurry with mass concentration of 64%presents an irregular“U”shape before the turning point while the other groups,however,are basically symmetric around the turning point.The experiments are designed to verify the prediction model,and the results show that the average error rate is 6.2%,with good adaptability.