Abstract: Based on elastic theory and reasonable assumption, the control differential equations have been put forward by adopting the load-transfer function method in order to research the load transfer mechanism of composite foundation of rigid piles with cap, including relations among pile settlement and its axial stress, vertical displacement of soil under pile cap and vertical stress of it, vertical displacement of soil besides pile cap and vertical stress of it, the friction force of pile-side, the soil friction force of the edge of pile cap and load level, depth in rigid pile with cap composite foundation. The corresponding analytical formulas have also been derived by using approximate solution method of differential equation. The calculation results can image basically the mechanical behavior rules of the load transfer for rigid pile with cap composite foundation according to the method proposed, using directly the relation of load-settlement of pile tests as known condition.

Key words: rigid pile with cap, load-transfer mechanism, soil under pile cap, soil besides pile cap, behavior rules