研究高浓度浆液流变特性随时间变化规律对采空区注浆充填有重要意义为准确掌握高浓度浆液在采空区中形成的堆积体大小与形态。选取水泥为胶结材料，标准砂为骨料，对不同骨胶比高浓度充填浆液流变参数随着时间变化规律进行研究。结果表明，剪切速率在0～60 s^-1递增过程中，浆液的剪切应力和表观黏度均会先突增至某一值然后下降；剪切速率在60～0 s^-1递减过程中，浆液的剪切应力和表观黏度为线性递减。剪切速率上升时对应的剪切应力和表观黏度均大于下降时的剪切应力和表观黏度，浆液具有触变性。剪切速率在60～0 s^-1递减过程浆液符合Bingham模型，且剪切速率减小过程更满足高浓度浆液充填采空区的实际工况。利用Bingham模型求得不同时间浆液塑性黏度和屈服应力，随着静置时间增加，高浓度浆液屈服应力和塑性黏度整体增加，触变性整体增加；相同静置时间下，骨料占比越多，浆液的塑性黏度和屈服应力越大。高浓度浆液随时间的流变规律主要受到硅酸三钙反应影响，生成的针状水化硅酸钙直接影响了不同静置时间下高浓度浆液的黏度、屈服应力和触变性，2 h以内，针状水化硅酸钙在砂颗粒之间的桥接作用使高浓度浆液的黏度、屈服应力和触变性都增加。水灰比一定，水泥水化反应一定，骨料越多，水泥浆液在骨料上形成的膜越薄，骨料之间生成针状水化硅酸钙越多。根据试验数据拟合了塑性黏度和屈服应力随时间的变化公式，为后续高浓度浆液充填工艺中关键参数设定提供一定的依据。

In order to accurately grasp the size and shape of deposits formed by high-concentration slurry in the gob, it is of great significance to study the rheological characteristics of the high-concentration slurry over time for the grouting filling in the gob. This paper makes a preliminary study of the effects of cement as cementitious materials and standard sand as aggregates on the rheological properties of high concentration filling slurry under a series of samples with different bone-cement ratios and time. The test results show thatwhen the shear rate is increasing from 0 to 60 s^-1, the shear stress and apparent viscosity of the slurry will suddenly increase to a certain value and then decrease. In the process of decreasing the shear rate from 60 to 0 s^-1, shear stress and apparent viscosity of the slurry decrease linearly. When the shear rate increases, the corresponding shear stress and apparent viscosity are greater than that when it decreases, and the slurry has significant thixotropy. When the shear rate decreases from 60 to 0 s^-1,the slurry conforms to the Bingham model, and the shear rate reduction process satisfies the actual working conditions of high concentration slurry filling the gob.Using the Bingham model to obtain the plastic viscosity and yield stress of the slurry at different times, it was found that as the standing time increases, the yield stress and plas tic viscosity of the high-concentration slurry increase as a whole, and the thixotropy increases as a whole. Under the same standing time, the more the proportion of aggregate, the greater the plastic viscosity and yield stress of the slurry. The rheological properties of high-concentration slurry over time are mainly affected by the tricalcium silicate reaction. The acicular hydrated calcium silicate directly affects the viscosity, yield stress and thixotropy of high-concentration slurry over time. Within 2 hours, the bridging effect of acicular hydrated calcium silicate between the sand particles increases the viscosity, yield stress and thixotropy of the high-concentration slurry. When the water-cement ratio is constant and the cement hydration reaction is constant, the more aggregate, the thinner the film formed by the cement slurry on the aggregates, and the more needle-like hydrated calcium silicate is generated between the aggregates. According to the experimental data, the formulas of plastic viscosity and yield stress with time are fitted, which provides a certain basis for the setting of key parameters in the subsequent high-concentration slurry filling process. 

0 引言

1 材料与方法

   1.1 试验材料及方法

   1.2 试验仪器

   1.3 试验原理

2 试验结果

3 机理分析

4 应用分析

5 结论