Simplified nonlinear method for settlement of root piles in multi-layered soils

The root pile is a new type of pile, which improves the bearing capacity by penetrating a certain number of horizontal roots into soils from the reserved position of the piles. The load transfer model for the roots of a root pile is proposed based on the hyperbolic function, and a simplified nonlinear method for settlement of the root piles in multilayered soils is derived. An effective computer program based on MATLAB is developed for nonlinearly analyzing the load-settlement behavior of the root piles. The comparisons among the proposed method, other analytical methods and the root pile load test results on sites are carried out in terms of two real case root piles in Chizhou Yangtze River Highway Bridge in Anhui Province, China. It is demonstrated that the proposed method can achieve a good agreement with the measured results, and the load-settlement curve calculated by this method is more consistent with the real load-settlement characteristics of the root piles compared with that of the other analysis methods. The parameter study of the root piles shows that the load-settlement behavior of the root piles is not sensitive to the layout of roots and the load transfer parameters selected at root side-soil interface, but sensitive to the load transfer parameters selected at root base-soil interface.