ABSTRACT
In this paper, the ultimate bearing capacity of single pile is used for the pile in friction pile groups with large pile spacing and low pile cap, and the loads acting on the composite pile foundations are distinctly shared by the piles and the soil under the cap. Based on the theory of composite pile foundations, the concept of plastically bearing pile is established. The methods of settlement calculation, the design principals of application and some problems of nonlinear design of composite pile foundations interaction are presented. These methods and concept have been used for the design of a library. The success of the field experimental studies of the library has fully verified the feasibility and advance of the research and it has a broad prospect in practical application.
