Analysis of axial load-transfer of large-diameter cast-in-situ tubular pile

Thin-walled cast-in-situ tubular pile is a new type of high quality pile, which has good application in soft ground treatment. Load transfer mechanism of tubular pile is different from that of ordinary cast-is-situ pile or sunk tubular solid pile and is not expatiated integrally till now because of the complexity of soil core mechanism which restrictes the development of the pile bearing theory and its practical application. The design method still lies in a semi-theoretical and semi-empirical state. As the soil strength is regarded as linearly varies along the depth, with linear elastic-plastic load transfer function, a set of analytical equations for the axial load-settlement curve of thin-walled cast-in-situ tubular pile are deduced to determine the vertical bearing capacity of pile according to the settlement of pile top. Correlative parameters of the pile-soil system can be got from fitting measured P-S curve. Then the distribution equations of axial force and friction along pile can be calculated. Case studies are given to validate the method.