Variable Stiffness Leveling Foundation Design and Analysis of CFG Composite Foundation

Beijing International Culture Silicon Valley Park is located in Chaoyang District, Beijing. The project area is mainly composed of silty clay, silty soil and sandy soil with high groundwater level. In this project the only-underground-building needs anti-floating piles. At the same time, due to large load of the main towers and insufficient foundation bearing capacity, the CFG composite foundation is adopted under the main towers. Thus, CFG composite foundation under the main towers and anti-floating piles under the only-underground-building are used in this project. The differential settlement between towers and only-underground-building and also the core tube and the outer frame column of the tower building is difficult to control. Through the calculation and analysis of differential settlement deformation based on the interaction between geotechnical foundation and structure, the engineering measures for controlling and coordinating differential settlement are verified. The measures include selecting reasonable bearing layer of CFG pile, adjusting the foundation stiffness by using different spacing of CFG piles and cushion thickness, and optimizing the anti-floating piles according to the geotechnical settlement deformation analysis. The variable stiffness between the towers and their skirt buildings as well as the core tube of the tower and the columns of the outer frame is realized. The design is verified by the engineering inspection and settlement measurement.