水泥固化锌离子污染土力学特性试验研究

Experimental study on mechanical characteristics of zinc ion contaminated soils stabilized by cement

水泥固化重金属污染场地在工程实践中取得了较好的处治效果,然而不同类型的重金属离子,由于其化学性质的差异,其相应的固化体物理力学性质也不同。本文基于锌离子污染土样,通过室内试验研究了不同浓度的污染物掺量下土样的强度及压缩特性,同时采用不同掺量的水泥对污染土样进行固化处理,并进行了相关强度及压缩试验。试验结果表明:锌离子会引起土样强度及压缩特性的劣化,但劣化程度较小,且离子浓度对其劣化程度影响较小;采用水泥对重金属污染土样进行固化,土的强度及压缩特性会显著增大,并随着水泥掺量的增加而提高;锌离子会显著抑制水泥的固化过程,当锌离子浓度达到1.25%时,7.5%的水泥掺量不能有效增强固化体强度及压缩特性。

The contaminated soils with heavy metal stabilized by cement are widely accepted in the engineering practice. However,because of the differences in chemical properties of the heavy metal ion,the mechanical characteristics of the stabilized soil are varied. Based on the soils contaminated by zinc ion,a series of strength and compression tests with different zinc ion concentration are conducted,and the contaminated soils are stabilized by cement. The test results show that zinc ion will cause the strength degradation of the soils, but the magnitude are relative small; the stabilized soils by cement have significant improvement in unconfined compressive strength and deformation characteristics, and the improvement effects are increased with the amount of cement; zinc ion will suppress the hydration process of the cement greatly,when the concentration of the zinc ion is 1. 25% or larger,the amount of 7. 5%cement will not improve the mechanical properties of the contaminated soil effectively.