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当压实膨润土在蒸馏水中膨胀后,施加于膨润土颗粒上的有效应力通常被认为是外部施加的荷载,而当膨润土在盐溶液中膨胀时,膨润土颗粒所承受的有效应力还包括由孔隙水渗透吸力所引起的渗透应力。而压缩膨润土的蒙脱石孔隙比e_m与膨润土颗粒承受的有效应力p之间满足分形关系,该关系可用来计算膨润土的膨胀变形。通过对压实膨润土在盐溶液中颗粒的分散情况以及颗粒表面的分形特性,推导出该渗透应力的表达式,进而得出膨润土颗粒所承受的有效应力。将所提出的有效应力代入分形模型中,计算GMZ01和MX-80膨润土在不同浓度NaCl溶液中的膨胀变形,将现有的两种膨润土膨胀试验结果与模型计算结果对比,发现具有较好的吻合度,在蒸馏水以及各浓度的盐溶液中膨润土的膨胀变形都可采用统一的e_m-p曲线表示,表明提出的有效应力符合膨润土颗粒在盐溶液中的实际受力情况。分形模型为研究膨润土在盐溶液中的膨胀性质提供了有效的计算方法。
The effective stress applied to the bentonite particles when the compacted bentonite is swollen in distilled water is generally considered to be an externally applied load, and when bentonite expands in salt solution, the effective stress that the bentonite particles are subjected to also includes the effect of penetration by pore water Permeate stress caused by suction. However, the fractal relation between the void ratio of montmorillonite and the effective stress p of bentonite particles is satisfied, which can be used to calculate the swelling deformation of bentonite. Through the dispersion of compacted bentonite in salt solution and the fractal characteristics of the particle surface, the expression of the infiltration stress is derived, and the effective stress that the bentonite particles bear is obtained. The proposed effective stress into the fractal model, calculated GMZ01 and MX-80 bentonite in different concentrations of NaCl solution in the expansion and deformation of the existing two kinds of bentonite swelling test results and model comparison results and found to have a good match Degree, the swelling deformation of bentonite in distilled water and salt solution of each concentration can be expressed by a unified e_m-p curve, indicating that the proposed effective stress conforms to the actual stress of bentonite particles in salt solution. Fractal model provides an effective method to study the swelling property of bentonite in salt solution.