铀尾砂水性聚氨酯固化体的力学性能研究

为研究水性聚氨酯对铀尾砂的固化效果，开展了不同质量比的水性聚氨酯固化铀尾砂试验，采用三轴压缩试验研究了水性聚氨酯质量比对铀尾砂试样的应力-应变行为、破坏强度、抗剪强度参数的影响，并采用扫描电子显微镜表征了固化前后铀尾砂的微观特征。结果表明，当水性聚氨酯的质量比为5%～10%时，随着围压的增加，试样的应力-应变曲线由软化型向硬化型转变；当水性聚氨酯的质量比为15%时，皆为强软化型。随着水性聚氨酯质量比的增加，试样的破坏强度增大，内摩擦角下降，内聚力提高。扫描电子显微镜表征表明水性聚氨酯通过充填到尾砂颗粒间的孔隙中，并将其包裹和黏结在一起，由此形成空间网状结构，提高了试样的力学性能。

Experimental Study on Mechanical Characteristics of Uranium Tailings Solidified by Waterborne Polyurethane Complex

To verify the solidification effect of waterborne polyurethane on uranium tailings, solidification experiments of uranium tailings using waterborne polyurethane with different mass ratio were carried out. The effects of the mass ratio of waterborne polyurethane to uranium tailings on the stress-strain behavior, failure strength and shear strength parameters of uranium tailings samples were investigated through triaxial compression tests. Furthermore, scanning electron microscope was used to characterize microscopic characteristics of uranium tailings before and after solidification. Experimental results showed that for the mass ratios of waterborne polyurethane to uranium tailings of 5%~10%, the stress-strain behavior of the solidified sample changed from strain softening to strain hardening with the increase of confining pressure; at a mass ratio of waterborne polyurethane to uranium tailings of 15%, the stress-strain behavior of the solidified sample exhibited strong strain softening. With the increase of the mass ratio of waterborne polyurethane to uranium tailings, the failure strength of the sample increased, the internal friction angle decreased, and the cohesion increased. Scanning electron microscope results showed that waterborne polyurethane was filled into the pores between tailings particles which were wrapped and bonded together. Therefore, the spatial reticular structure was formed, resulting in the improvement of the mechanical properties of the samples solidified by waterborne polyurethane.