Abstract: Based on the elasto-plastic solution to the cavity expansion for jacked piles problems in natural saturated clay, an analytical solution to the excess pore water dissipation around the pile is derived with aid of the stress state of the soil immediately after pile installation. On this basis, a theoretical method for calculating the time-dependent bearing capacity of the jacked pile in natural saturated soil is presented by considering the soil relaxation effects on the soil around the pile during reconsolidation of the soil. The theoretical method is verified by the published centrifuge model test and field test respectively, and the variation of the bearing capacity of the jacked pile with consolidation time is studied in detail. The results show that the proposed theoretical method can be applied to reasonably predict the time-depended bearing capacity of the jacked pile, because the in-situ mechanical property of the soil, the installation effect, as well as the reconsolidation effect after installation are properly considered by the proposed method. The results of this paper have great theoretical significance in proper determining the bearing capacity of a jacked pile in clay.

Key words: effective stress, reconsolidation, soil relaxation, centrifuge test, time-dependent bearing capacity