煤粉剪切特性及其影响因素分析

为了研究煤粉的剪切特性及其影响因素，借助ShearTrac Ⅱ剪切系统，获得了煤粉的屈服轨迹，并将煤粉与典型粉体玻璃微珠的剪切特性进行了比较，分析表明煤粉更难剪切，因此重点研究了剪切速率、剪切位移和预压应力对煤粉剪切特性的影响。Jenike剪切标准D6128 00的剪切速率范围(1~3 mm/min)对煤粉介质依然适用，在此范围内可适当提高剪切速率以节省测试时间；为确保煤粉介质达到剪切峰值并进入稳态区，剪切位移设计应不小于8 mm。此外，煤粉内聚力和流动指数随着预压应力的增加而增大，应根据实际应用选择与其相对应的预压应力范围。

Shear Performance of Pulverized Coal and Its Influencing Factors

To investigate the shear performance of pulverized coal and its influencing factors, the yield locus of pulverized coal were obtained by ShearTrac II system. Shear characteristics of pulverized coal and typical powder glass beads were compared. The results show that shearing of pulverized coal is more difficult. Furthermore, the effects of shear velocity, shear displacement and preconsolidation stress on shear characteristics are determined, indicating that the recommended shear velocity (D6128 00), ranging from 1 mm/min to 3 mm/min, is available for pulverized coal. The increasing shear velocity during this range has little effect on the stress measurements but saves test time. To ensure achieving the peak value and the steady state region of shear stress, the shear displacement should be more than 8 mm. The cohesion and flow index increased gradually with the rising preconsolidation stresses, thus, the selection of which should be based on the intended application.