细粒含量对高应力尾砂不排水剪切强度特性的影响

Effect of Fines Content on Undrained Shear Strength of Tailings Under High Stress

通过三轴固结不排水试验,对饱和尾砂的剪切强度特性和颗粒破碎特性进行研究,讨论了试验中尾砂在不同细粒含量和围压条件下的应力-应变关系、孔隙水压力特性、应力路径和颗粒破碎程度。试验结果表明:在细粒含量小于15%时,高应力尾砂的剪切强度和软化程度随细粒含量的增大而减小。增加细粒含量使得孔隙水压力达到更高值,不同细粒含量时应力路径均属于完全软化-剪缩模式。颗粒破碎程度随着细粒含量的增大而减弱,且颗粒破碎程度与围压之间呈幂函数型增长关系。为此,建议在实际工程中尽可能采用粗颗粒尾砂筑坝,或采取其他工程措施,以提高尾矿坝体的稳定性。

The shear strength and particle breakage characteristics of saturated tailings were studied by the consolidated undrained triaxial （CU） tests. The stress-strain relationship, pore water pressure characteristics, stress path, and particle break- age degree of tailings sand were discussed under different fines content and confining pressure. The testing results showed that, the shear strength and stress softening degree of the high stress tailings are decreased with fines content increasing at the fines content less than 15%. The increase of fines content leads the pore water pressure to a higher value. The stress path is com- pletely softening-contractive model under different fines content. The breakage degree of particles is decreased with fines con- tent increasing, and there is a power function growth relationship between particle breakage parameters and confining pressure. Therefore, in order to improve the stability of tailings dam, the scheme of coarse particle tailings used to build dam in practice projects was proposed, or taking other engineering measures.