Mechanism Analysis on Combined Toe-and-side Grouting for Cast-in-situ Piles

Based on the construction technology of post-grouting, the load transfer mechanism, bearing capacity increasing mechanism and variation of pile-side and pile-toe resistance of combined toe-and-side grouted pile are analyzed. The mechanism of increasing of pile-side resistance and pile-tip resistance by post-grouting are discussed. It is believed that the increase of pile-side resistance by post-grouting relies largely on the improvement of pile-soil interface, improvement of mechanical property of pile-around soil and expanded-base effect of increased pile diameter. The increase of pile-tip resistance by pile-toe post-grouting mainly depends on improved mechanical property of pile-toe soil, change of pile-end destruction form, and expanded-base effect by increased pile-toe diameter.