The mechanism of the effect of salt solution on the water retention capacity of compacted clay is studied from the microscopic perspective. Based on the fractal theory and the double-porosity characteristic of compacted clay, the fractal model and dual-porosity model for predicting the soil-water retention curve of compacted clay are established. And the gravimetric water content and matric suction calculated from the pore size distribution data in the relevant literature are fitted by the established models. Results show that there is a “flat section” caused by the dual-porosity structure of compacted clay in the soil-water retention curve, which tends to be lower with the increase of salt solution concentration. In this case, the dual-porosity model fits the data better than the fractal model. The soil-water retention curve shows no “flat section” for the compacted clay with inconspicuous dual-porosity structure. Due to the inhibition of the formation of the diffusion double layer, the reduction of macro-pore volume is prevented during hydration. The chemical correction equation for the fitting parameters is also established, which well reflects the change of the fitting parameters with the concentration of solution by using the two models to predict the soil-water retention curves of compacted BES (ρ_d = 1.5 Mg/m³) and compacted FEBEX bentonite (ρ_d = 1.65 Mg/m³). The modified parametric equation is substituted into two models, and subsequently the modified soil-water retention model considering the effect of pore structure and chemical solution is obtained.

从微观角度研究盐溶液对压实粘土保水能力影响的机理。基于分形理论和压实黏土的双孔隙特性，建立了用于预测压实黏土水土保持曲线的分形模型和双孔隙度模型。并根据相关文献中的孔径分布数据计算得到的重量含水量和基质吸力与所建立的模型进行拟合。结果表明，土壤保水曲线中存在由压实粘土的双孔隙结构引起的“平坦段”，随着盐溶液浓度的增加，该“平坦段”趋于降低。在这种情况下，双孔隙度模型比分形模型更适合数据。双孔隙结构不明显的压实粘土的保水曲线没有“平坦截面”。由于抑制了扩散双层的形成，防止了水化过程中大孔体积的减少。还建立了拟合参数的化学修正方程，利用这两种模型对压实BES的土壤保水曲线进行了预测，较好地反映了拟合参数随溶液浓度的变化。ρ _d  = 1.5 Mg/m ³ ) 和压实的 FEBEX 膨润土 ( ρ _d  = 1.65 Mg/m ³ )。将修正后的参数方程代入两个模型，进而得到考虑孔隙结构和化学溶液影响的修正后的土壤保水模型。