It is well established that clays can exhibit semipermeable membrane behavior and osmotic efficiency is used to describe the membrane behavior of clays. Several experimental results have already verified that osmotic efficiency is not constant when pore-fluid chemistry changes. In this article, based on the mechanical balance, generalized Darcy's law and the principle of mass conservation, an improved fully coupled hydro-chemo-mechanical model is proposed for saturated clayey materials, in which osmotic efficiency is treated as a variable that depends on the solute concentration, grain density, porosity of soil, and cation exchange capacity. Numerical simulations are conducted to investigate the influence of variable osmotic efficiency on solute transport. The results show that solute transport is very sensitive to osmotic efficiency and when the transport time is 10 years, the difference in influence depth reaches about 13.6 cm with constant (0.069) and variable (initially 0.069) osmotic efficiencies, this indicates that semipermeable membrane behavior of clays with variable osmotic efficiency restricts the solute transport effectively and slows down the solute movement strongly. The difference in breakthrough time reaches 15.8 years with osmotic efficiency (0.069). The proposed coupled model can be used to guide the design of clay liners and evaluate their service performance.

中文翻译：

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粘土可变膜行为对溶质运移的影响

众所周知，粘土可以表现出半透膜行为，渗透效率用于描述粘土的膜行为。一些实验结果已经证实，当孔隙流体化学变化时渗透效率不是恒定的。本文基于力学平衡、广义达西定律和质量守恒原理，提出了一种改进的饱和黏土材料全耦合水-化学-力学模型，其中渗透效率被视为取决于溶质浓度、颗粒密度、土壤孔隙度和阳离子交换能力。进行数值模拟以研究可变渗透效率对溶质运输的影响。结果表明，溶质运移对渗透效率非常敏感，当运移时间为 10 年时，影响深度的差异达到约 13.6 cm，渗透效率恒定（0.069）和可变（初始 0.069），这表明半透膜行为具有可变渗透效率的粘土有效地限制了溶质运输并强烈减慢了溶质运动。渗透效率 (0.069) 的突破时间差异达到 15.8 年。所提出的耦合模型可用于指导粘土衬垫的设计并评估其使用性能。这表明具有可变渗透效率的粘土的半透膜行为有效地限制了溶质运输并强烈减慢了溶质运动。渗透效率 (0.069) 的突破时间差异达到 15.8 年。所提出的耦合模型可用于指导粘土衬垫的设计并评估其使用性能。这表明具有可变渗透效率的粘土的半透膜行为有效地限制了溶质运输并强烈减慢了溶质运动。渗透效率 (0.069) 的突破时间差异达到 15.8 年。所提出的耦合模型可用于指导粘土衬垫的设计并评估其使用性能。