new idea to design a composite raft foundation consisting of sand layer and concrete plate isillustrated in this paper .

The choices of structural styles and structural features of Zhongguancun Dingdu plaza for science and technology are introduced, also with the design methods for raft foundation with column cap.

Applying raft lamination foundation to the treatment of soft foundation, we take effective measures to solve our problems in the work.

Discussion on design method of raft foundation;

Combined with one practical project in which the CFG pile composite ground was adopted,the design method of CFG pile composite ground of column-raft foundation is elaborated with the foundation rigidity and load distribution considered in order to make safe,economical and rational ground and foundation plan.

The design and calculation of raft foundation,the topic of whether to remain the permannent building separation for settlement between mair buildings and podiums,the piling design,and calculation for base settlement are introduced.

The water-proof and permeability-proof processing methods on the line of gap settement for raft foundation are discussed when it is under the groundwater level.

In order to make use of the underground space well, thick raft foundation is adopted more.