A New Load Transfer Model of Skin Friction for Super-long Pile Under Axially Load

In present investigation, a new load transfer model was proposed, in which the softening and strengthening of super-long pile skin friction was considered. The influence of parameters variation on the softening load transfer model was discussed in detail. The load transfer model proposed was verified by engineering results. The nonlinear iterative calculation method of the super-long piles was improved with considering the nonlinear compression model of concrete and the weight of the pile body. Comparing calculation results and the engineering measured data, it demonstrates that the relationship between pile skin friction and the relative displacement and the settlement results are generally in good agreement with the practical engineering results. The skin friction of super-long piles increases with the increase of the depth, while decreases with the increase of the depth near the end of the pile and it has an obvious downward trend. As the load continues to increase, the skin friction near the pile end increases significantly and shows a gradual expansion of the pattern. It completely reflects the softening and strengthening properties of pile skin friction.