Cement-Soil and R.C combined piles are a new measure for retaining and protecting excavations of building foundation

with R.C piles being inserted into Cement Deep Mixing piles.This new type of multiplex pile simultaneously has both functions of bear loadings and cutting off water.Use of Door-typed piles

with fore-and-aft rows connected with circular beam

can improve the mechanical function of retaining structure.This new technique has been applied successfully in a deep excavation in Nanjing.The design details of structures and computation results are presented in this paper.Comparisons are made between numerical monitoring data.It is shown that the new type of pile is a cost-effective retaining structure and can find wide application in deep exactions for building foundations.