In the complex chemical environment of municipal waste landfills, the chemo-hydro-mechanical coupled flows in the compacted clay layer (CCL) and its deformation are very complicated. When studying the chemo-hydromechanical consolidation of soil, the osmotic flow, ultrafiltration, and the osmosis effect on solute migration were neglected due to the low osmotic efficiency. However, the permeability of CCL of landfill is very small, and their osmotic efficiency is higher. The osmotic phenomenon and influence of osmotic efficiency must be considered. In this paper, a 1-D chemo-hydro-mechanical coupled model of saturated soil is proposed considering osmotic efficiency. The analytical solutions of the model under specific boundary conditions were obtained by Fourier transform. The degradation model is compared with the existing governing equations and results in the literature, and the correctness of the proposed governing equations and analytical solutions is verified. Through the analysis of specific case, it can be concluded that chemo-osmotic consolidation significantly affects the consolidation of the soil layers. The osmotic consolidation leads to the generation of negative pore pressure, but it decreases with the decrease of the osmotic pressure gradient. This process leads to the rebound effect of the soil settlement. The osmotic efficiency significantly affects the consolidation characteristics of this soil layer, and therefore the effect of osmotic efficiency must be considered in soils with high osmotic efficiency.

In geological sites containing chemical pollutants, the clay buffer layer (CBL) is frequently utilized to isolate the pollutants from the external environment. Moreover, hydraulics, mechanics, and chemistry jointly pose impacts on the consolidation of CBL and the diffusion of chemical substances. In order to consider the coupled effect (termed chemo-hydro-mechanical-CHM), a one-dimensional consolidation model that fully considers CHM coupling (such as convection, ultrafiltration, and osmotic efficiency) is established. In the developed model, the excess pore pressure, chemical concentration, and soil settlement during the consolidation process are calculated via finite Fourier transform and inverse transform. Finally, the CHM coupling effect on consolidation under different conditions is analyzed and discussed. The results indicated that the coupling effect slowed down the entry of chemical substances into the soil layer so that the excess pore pressure dissipated faster, and the negative pore pressure was larger. Furthermore, the coupling effect increased the maximum settlement during consolidation but did not change the final settlement. The coupling effect prolonged the time of consolidation. In addition, the higher the osmotic efficiency, the greater the coupling effect, but the osmotic efficiency did not affect the time of consolidation.

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In this paper, a simplified chemo‐hydro‐mechanics (CHM) model, in which only solute concentration is considered in the aspect of chemistry, is proposed to reflect the viscoelastic deformation of clay soil. By using the proposed model, the responses of the excess pore‐fluid pressure, solute concentration, and displacement of the viscoelastic clay soil are derived through the Laplace transform method. Then, semi‐analytical solutions, in the time domain, are obtained via the inverse Laplace transform numerically. The influences of viscosity on excess pore‐fluid pressure, solute concentration, and displacement are investigated through an illustrative example. The results show that: (1) the clay soil in low viscosity can be simplified as an elastic model; (2) the higher viscosity not only accelerates the dissipation of excess pore‐fluid pressure, but also slows down the deformation of the clay soil; (3) the viscosity of clay soil poses little impact on the distribution of solute concentration.