An analytical method is developed for solving the coupled chemo-hydro-mechanical consolidation in a clay buffer layer under time-dependent loading. The coupled governing equations for the chemo-hydro-mechanical process are established in the time and spatial domain first. Then, the governing equations are decoupled into two partial differential equations by introducing two variables. The analytical solutions corresponding to ramp and exponential loadings are finally derived based on the initial and boundary conditions. The developed analytical solutions are verified via comparing with the numerical results simulated by COMSOL Multiphysics. Based on the developed solutions, selected parametric study is carried out to investigate the influence of major parameters and hydraulic boundary conditions on the contaminants transport and pore water pressure dissipation in buffer clay layer. The results show that the major parameters have effects on the generation and dissipation of pore pressure, while only effective coefficient of diffusion, coefficient of ultrafiltration, and relative change of total density of pore liquid significantly affect the contaminant migration process. Compared with a single drainage boundary, the pore pressure dissipation and contaminant migration in a double drainage soil layer are much faster. The longer the loading time of mechanical loading, the more significant the negative pore pressure caused by the concentration gradient.

To comprehensively consider the influence of boundary conditions, non-Darcy flow, load forms, and soil stratification on soil consolidation, a one-dimensional soil consolidation equation is established. By subdividing the soil layer and employing time discretization, the nonlinear consolidation equation is linearized, resulting in an analytical solution for layered soil foundation at any given time. Subsequently, an iterative approach for time solution is employed to obtain a semi-analytical solution. The correctness of the solution is verified by comparison with solutions based on Darcy's flow and the semi-analytical method under traditional drainage boundary conditions. Subsequently, the influence of interface parameters, loading conditions, flow index, and other factors on consolidation characteristics is analyzed. The results indicate that higher interface parameter values for continuous drainage boundaries correspond to faster average consolidation rates for stratified soil foundations, while these parameters have little effect on the time required for complete consolidation of the soil layers. Improved boundary drainage performance amplifies the influence of exponential flow on pore water pressure and average consolidation degree. Conversely, poor boundary drainage performance diminishes the impact of exponential flow on soil consolidation, rendering it negligible. Moreover, faster loading rates accentuate the influence of the flow index on the average consolidation degree defined by pore pressure.

This paper presents a consolidation model for stone column-reinforced soft ground subjected to time-dependent loading under free strain condition. Smear effects and three types of loadings, namely, constant loading, ramp loading, and sinusoidal loading, are considered in the developed consolidation model, which is solved by a numerical method based on a partial differential equation solver. The applicability of the proposed consolidation model and the reliability of the numerical method are demonstrated and verified by well-predicting the consolidation behaviors of two practical engineering cases and one laboratory experiment. The verified model and the numerical method are then employed to investigate the effects of smear zone and time-dependent loading on consolidation characteristics of stone column-improved soft ground. The results indicate that the excess pore water pressure undergoes a sharp change at the interface between the smear zone and the undisturbed zone due to smear effects. The smaller the range of the smear zone, the faster the settlement of the composite foundation develops. The faster the loading rate, the faster the dissipation of excess pore water pressure and the faster the settlement develops. In addition, for the foundation subjected to sinusoidal loading, the higher loading frequency results in a larger amplitude corresponding to the excess pore water pressure and a smaller amplitude corresponding to the settlement of the soil.

In this paper, the one-dimensional rheological consolidation characteristics of multilayered saturated soil foundations under time-dependent loading and heating are investigated by considering the semi-permeability and the interface thermal resistance. By introducing the fractional derivative model and the thermos-elastic theory, a thermo-mechanical coupling model is established to describe the rheological properties of saturated soils. Semi-analytical solutions for strain, temperature increment, pore water pressure and settlement were derived through the Laplace transform and its inverse. The accuracy of the solutions proposed in this paper has been verified by comparing with existing solutions. The effects of different thermal contact models of the interface on the rheological properties of saturated soils under semi-permeable boundary are discussed, and the effects of fractional derivative order, constitutive material parameters, and thermal conductivity of soil on the thermal consolidation process are investigated. The results show that: neglecting the thermal resistance effect can result in an overestimates of the impact of rheological properties on the thermal consolidation process of saturated soils under semi-permeable boundaries; As the thermal resistance coefficient increases, the influence of soil thermal conductivity on settlement decreases.

The large strain and nonlinear consolidation characteristics of soft soils with high compressibility have obvious effects on their consolidation, but few analytical solutions for large-strain nonlinear consolidation of soils with vertical drains have been reported in the literature. By considering the large deformation characteristics of soft soils with high compressibility during consolidation, a large-strain nonlinear consolidation model of soils with vertical drains is developed and an analytical solution for this consolidation model is obtained based on Gibson's large deformation consolidation theory, in which a double logarithmic nonlinear compressibility and permeability model is adopted to describe the variation of the compressibility and permeability of soft soils. The proposed analytical solutions are compared with the numerical solutions of large-strain nonlinear consolidation of soils with vertical drains and the analytical solutions of small-strain linear consolidation under specific conditions to verify its reliability. On this basis, the nonlinear consolidation properties of soils with vertical drains under different conditions are analyzed by extensive calculations. The results show that the consolidation rate increases with decreasing the permeability parameter alpha, when the compression index I-c, keeps constant. The consolidation rate increases with decreasing the compression index I-c, when the permeability parameter alpha remains constant. The consolidation rate of soils with vertical drains increases with an increase in external load, and decrease with an increase in the ratio of influential zone radius to vertical drain radius when the compressibility and permeability parameters remain constant. Finally, the proposed analytical solution is applied to the reclaimed foundation treatment project of Shenzhen Western Corridor boundary control point(BCP). The settlement curve calculated by proposed solutions is in good agreement with the measured curve, which further illustrates the engineering applicability of the proposed analytical solution.