| Because of the high horizontal and vertical loaded capacity as well as the good resistance to uneven settlement, piled raft foundations are widely used in the thick soft soils in coastal areas. As a result, the research of interactions between superstructure and foundation is a constant hotspot in the geotechnical engineering. With the development of the economy and society, modern buildings become more novel and complicated, the loads from their structure increase as well. All of these characteristic require the groundwork more stable and thicker. The raft rigidity directly affected by the dimensions of the board, however, were neglected in the traditional analyzing of substratum settlement except of the elasticity theory method. Based on "the simplified method to analyze soil-pile-raft interactions", this article considers the raft rigidity of foundations and constructs an iterative algorithm to satisfy the concerted deformation.Firstly, this paper analyzes the distribution of pile-top counter force, pile-end resistance and additional stress of the substratum influenced by raft rigidity in different loads and piles length. It proves the internal forces of foundations distribute unevenly. The distribution of pile-top counter force and pile-end resistence influence the distribution of substratum's additional stress, and the latter farther influences the pile-top counter force inversely. Contrasted to the result by Geddes' formula, the same characters can be concluded.Subsequently, the thesis improves the simplified method, and puts forward an iterative algorithm to consider the influence by raft rigidity to substratum settlement and stab deformation. Then, numeric examples are calculated to testify its validity.Finally, the application of the method is introduced on a factual project and differences between the simplified method and the improved method are discussed. At the end of the paper, some guidable conclusions are gained.
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