Abstract: The phenomenon that the well resistance changes with both time and depth (i.e., the decrease of drainage capacity caused by silting and bending) has been widely concerned during the consolidation of soft soils with vertical drains. Moreover, the influence of variable well resistance on consolidation rate of soft soils with vertical drains cannot be ignored. However, there are few analytical solutions for consolidation which can consider the time-dependent loading and the variation of well resistance with time and depth at the same time. Considering the evolution process of time-and depth-dependent well resistance, a consolidation model of soft soils with vertical drains is developed by incorporating a single stage loading or a multistage loading which is widely adopted in practice, and the analytical solution of the consolidation model is obtained by using the separation of variables method. The correctness of the model is fully verified by comparison with the existing analytical solutions, finite difference solutions and engineering measured values. Finally, the influences of variable well resistance parameters on consolidation behavior of soft soils with vertical drains are analyzed through a lot of calculations. The results show that the consolidation rate of soft soils with vertical drains increases with an increase in the final drainage capacity of vertical drains, and decreases with an increase in the value of depth resistance parameters and time resistance parameters, and influences of time resistance parameters on the rate of consolidation are more significant.

Key words: consolidation of soft soil, variable well resistance, time-dependent loading, vertical drain, analytical solution