不可动水对土壤污染物运移影响的数值实验研究

The Numerical Experimental Study on the Effect of Immobile Water on Contaminant Transportation in Soil

考虑对流、弥散、吸附/解析、微生物降解等因素,建立了土壤中污染物运移的两区平衡吸附动力学模型.在该模型基础上,针对不可动水对污染物运移的影响进行了分析.分析结果表明:即使在孔隙水流速、含水率及其它参数相同的情况下,不同的iθm/mθ值也会导致不同的穿透曲线;不可动水所占的比例较大时,即使保证了孔隙流速、输入浓度、弥散系数等参数相同,不同的含水率也会导致不同的穿透曲线,但iθm/θm较小时,含水率的变化对浓度的变化几乎无影响.

The two-region model for contaminant transport in soil has been established considering the convection, diffusion, equilibrium absorption-desorption and microbiological degradation. On the basis of the model, the effect of the immobile water on contaminants transport in soil was analyzed. The results showed that in spite of the same values of pore water velocity, water content and other parameters, the different value of θim/θm may cause the different breakthrough curves; when the proportion of immobile water was higher, in spite of the same values of pore water velocity, input concentration and dispersion coefficient etc, the different values of water content may cause the different breakthrough curves, but when the value of θim/θm was very small, the differences of water content almost had no effect on the concentration.