摘要
含有硫酸盐及盐酸盐等高含盐量的地下水环境,对固化/稳定法处置的重金属污染土的工程性质可能存在一定的影响,进而直接影响土体的固化效果。通过系统的室内试验,着重研究水泥固化铅污染土在Na Cl溶液侵蚀环境下的强度特性和微观结构特征。试验结果表明,固化土的无侧限抗压强度随着Na Cl溶液浓度的增加而减小,压缩性随Na Cl浓度的增加而增大。浸泡7 d时,其强度最小,压缩性最大;超过7 d后,强度随浸泡时间的增加而增大,压缩性则随之减小。三轴试验结果表明,固化土的应力–应变特性大致分为弹性变形、塑性屈服和破坏阶段3个不同阶段。由于Na Cl的侵蚀作用,浸泡7 d的固化土中孔隙增多,结构较为疏松,浸泡28和90 d试样的颗粒排列较7 d要致密规则。
Under the groundwater environment that is rich in sulfate and chloride ions,solidified/stabilized heavy metal contaminated soils may suffer secondary pollution and resulting in the deterioration of solidification effectiveness. Thus, the strength and microstructure characteristics of cement solidified/stabilized lead contaminated soils under the secondary pollution by sodium chloride solution were studied. A systemic experiment program was performed on the cement solidified/stabilized Pb2+ contaminated soil. Test results show that the unconfined compressive strength of solidified soils decreased and compressibility increased with the increased in concentration of sodium chloride solution. The strength reached minimum and compressibility reached maximum when specimens soaked for 7 days. After soaking for more than 7 days,with the immersion time increased,the strength enhanced and the compressibility decreased. The results of triaxial compression test show that the stress-strain curves of solidified soils can be divided into three different sections:elastic deformation stage,plastic yielding stage and failure stage. Scanning electron microscopy(SEM) results indicate that erosion of sodium chloride solution leaded to porosity increased and loose structure of the solidified soils. Particles of the sample that soaked 28 and 90 days arranged more compactly and steadily than that soaked 7 days.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2015年第S2期4325-4332,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(41172273
41372281)
关键词
土力学
固化稳定法
NaCl侵蚀
铅污染土
强度
微观结构
soil mechanics
solidification/stabilization method
sodium chloride erosion
lead contaminated soil
strength
microstructure
