General Approximate Analytical Solutions for One-Dimensional Nonlinear Consolidation of Soft Soils under Time-Dependent Loading

A surcharge preloading method with time-dependent loading is widely used for accelerating the consolidation process of soft soils, and different loading patterns have a great effect on the consolidation characteristics. For one-dimensional nonlinear consolidation of soft soils considering the variable compressibility and permeability, the general approximate analytical solutions for one-dimensional nonlinear consolidation under time-dependent loading are derived. Moreover, two forms of boundary conditions are considered according to engineering practice. With reference to the general analytical solutions presented, the expressions for the solutions under several common loading patterns, such as the multistage instantaneous loading pattern, multistage linear loading pattern, and cyclic loading pattern, are given. The accuracy and correctness of the approximate analytical solutions are proven by comparing the approximate analytical solutions with the finite-difference solutions and two experimental results with different boundary conditions. Based on the approximate analytical solutions proposed, the consolidation behaviors of soft soils under different loading patterns are analyzed. In conclusion, the proposed approximate analytical solutions have a simple and clear form, which is convenient for calculations in engineering applications.