Abstract: Based on virtual soil-pile model, the influence analysis of pile tip soil properties on single pile settlement is conducted in terms of layered soils. Firstly, considering stress dispersion in soil medium, the soil between pile tip and bedrock surface is assumed to be virtual soil-pile. Furthermore, the virtual soil-pile with variable cross-section is divided into finite segments. Then, the surrounding soil layers of pile is modeled as ideal elastoplastic transfer model; and regarding the developmental plastic depth as an independent variable, a recursive method for calculating axial force and side friction of pile in layered soil is derived by load transfer method. On this basis, parameters selection of load transfer model is studied; meanwhile, the factors of virtual soil-pile length and the feasibility of acquiring stress dispersion angle through inversion analysis are analyzed. Finally, by means of the presented method, the difference of load-displacement curves has been examined when pile bottom sediment and soft substratum exist. The results show that: the calculated load-displacement curves of pile tip and pile top agree well with the measured curves considering stress dispersion of pile tip soil; the presented method can take the influences of pile bottom sediment and soft substratum on load-displacement curves into consideration.

Key words: settlement characteristics of single pile, virtual soil-pile model, load transfer method, stress dispersion, pile bottom sediment, soft substratum