Concept on plug development in jacked open-ended piles in clay considering total stresses

Soil plugging in open-ended piles is likely to occur in dense sandy soils which has been the subject of numerous scientific investigations. In contrast, the plugging behaviour in clayey soils is relatively unknown. In this paper an analytical approach to determine the soil plug resistance and its development during jacking in clayey soils is proposed. The new approach was developed using numerical simulations and was validated by back-calculating a field test from the literature. A total stress approach for the numerical simulations was chosen. The values calculated with the analytical formulas and the numerical solutions as well as the measurements from field tests are in very good agreement, given the high complexity of the interactions between pile and soil. Both the plug resistance and the plug height can be calculated during the jacking process. Further research is required to refine the proposed approach for soil plug resistance evaluation, as the proposed method is believed to enhance the understanding of occurring mechanisms.