Abstract: Abstract: Foundations of pile or CFG pile composite foundations for high-rise buildings in Xi'an are used widely. In some areas of the Weihe terraces, there are thick dense sand layers with good engineering performance.In this paper, an 100m building with frame tube structure in Xi'an is introduced.The analysis foundation scheme, in-situ static load test, determination of foundation bearing capacity, calculation of weak underlayer, calculation of foundation deformation are conduceted; The measures such as adjusting the size of the external raft of the foundation raft, rationally dividing the post-settling zone of the raft, and making the center of gravity of the building and the centroid of the raft foundation plane basically coincide are adoted; Combined with the analysis of the settlement observation data during the two years after the structure was capped,The feasibility of shceme for high-rise frame-tube structure to use fine sand layer as natural foundation has been proved.