不同迁移条件下铜污染红土的强度特性研究

Research on strength characteristic of copper contaminated laterite under different migration conditions

以云南红土为污染对象、CuSO_4为污染物,考虑CuSO_4溶液浓度、迁移时间、土柱深度等因素,通过土柱迁移试验、直剪试验,研究迁移条件下铜污染红土的抗剪强度特性,分析污染物与红土间的相互作用。结果表明:迁移条件下,总体上铜污染会引起红土抗剪强度减小;随CuSO_4溶液浓度的增大、迁移时间的延长,污染红土的抗剪强度呈降低的趋势;随着土柱深度的增大,抗剪强度呈先减小再增大再减小循环波动的形式,最终趋于平缓。CuSO_4与红土的相互作用过程包括水解、侵蚀、胶结和溶解作用,红土抗剪强度的变化正是这四种作用综合影响的结果。

The shear strength characteristic of copper contaminated laterite of Yunnan under migration condition and interaction between contaminant and laterite are studied according to the migration of soil column test and direct shear test using CuSO_4 as contaminant,considering the concentration of CuSO_4 solution,migration time,depth of soil column and other factors. The results show that copper contamination will cause shear strength of laterite decreases,with the concentration of CuSO_4 solution increasing and migration time extending,the shear strength of copper contaminated laterite decreases; with depth of soil column increases,the shear strength decreases firstly and then increases and then decreases cycle fluctuation,eventually becoming flat. The interaction between CuSO_4 and laterite includes hydrolysis,erosion,cementation and dissolution,the change of shear strength of laterite is the result of these four effects.