多级堆排尾矿沉积固结特性实验研究

基于多级堆排尾矿浆体沉积柱一维沉积固结实验,近似模拟一级尾矿子坝内堆排尾矿的沉积固结过程,针对不同排水控制条件下实验尾矿的沉积固结结果进行比较分析,探讨多级堆排尾矿的沉积固结规律。结果表明:尾矿浆体的沉积固结过程明显分为沉积和固结二个阶段;超静孔隙水压力前期消散迅速,后期消散缓慢;排水实验每日平均渗透系数前期逐日下降,后期小幅上升;不同排水控制条件下,固结完成尾矿的干密度及相对密实度均随深度的增加而增大,二者在排水实验各深度处均大于不排水实验。

Sedimentation and consolidation behaviors of the multilayered tailings

The process of sedimentation and consolidation of the fine particles in the high-density tailing slurry has an important influence on dam structure. In this paper, the unidimensional sedimentation and consolidation experiments were conducted on columns of the multilayered tailing slurries,to replicate the construction process of one tailing subdam and investigate the characteristics of the tailing slurry sedimentation and consolidation. The evolutions of daily average permeability coefficient and pore water pressure of the multilayered columns were observed, and the vertical distributions of dry density and relative compactness along the columns after the same experimental duration were discussed. Due to the self-weight sedimentation of tailing particles, the slurry gradually turned into the colloid-type material with a higher density. The process of sedimentation and consolidation of the fine particles in the high-density tailing slurry has an important influence on dam structure. In this paper, the unidimensional sedimentation and consolidation experiments were conducted on columns of the multilayered tailing slurries, to replicate the construction process of one tailing subdam and investigate the characteristics of the tailing slurry sedimentation and consolidation. The evolutions of daily average permeability coefficient and pore water pressure of the multilayered columns were observed, and the vertical distributions of dry density and relative compactness along the columns after the same experimental duration were discussed. Due to the self-weight sedimentation of tailing particles, the slurry gradually turned into the colloid-type material with a higher density. With the compaction of upper tailing particles and continuous drainage consolidations, the lower colloid-type tailings turned into some porous media with a certain extent of strength. Experimental results indicated that the settlement speed of the tailing surface slowed down suddenly, indicating all processes of sedimentation and consolidation of tailing slurry under drained and undrained experiments could be divided into two distinct stage: the sedimentation stage and the consolidation stage. The excess pore water pressure dissipated rapidly in the early period and the dissipation speed slowed down in the late period. The dry density and the relative compactness increased with the depth from tailing surface, but both increments in the drained experiment were larger than those in undrained experiments at the same depth. Moreover, it was observed that the daily average permeability coefficient in the drained experiment decreased with respect to time in the early period but recovered slightly in the later period.