Abstract: In the foundation design of a mansion in Hangzhou, the variable foundation rigidity design is adopted for reducing differential settlement, and the optimum design for piles and raft plates is used. Supporting course and type of piles are selected. Transformation of compressive modulus and pile-stiffness after post-grouting is analyzed. By means of JCCAD, the differential settlement between the main building and the podium is calculated and compared with the field results.