Study on negative friction of pile foundation in homogeneous layered soil in collapsible loess area.

The collapsible nature of loess soil can lead to issues such as additional settlement of pile foundations, reduced pile strength, and decreased bearing capacity, posing a significant threat to the safety of structures in loess regions. In this paper, considering the collapsibility of loess and the layered characteristics of foundation soil, a load transfer model for single piles in homogeneous layered soil was established using the load transfer method. Simultaneously, based on the elastoplastic theory, a differential equation controlling the negative skin friction of single piles caused by the collapsibility of loess was derived.