Bearing Characteristics of Pile-end Post-grouting Pile of Xi′an Xianyang International Airport Expressway Bridge

Two different techniques,pile-end post-grouting technology of bored piles and conventional cast-in-place piles,were used to conduct the in-situ static loading tests on the pile foundation of the Weihe Bridge K3+966.50 of Xi'an Xianyang International Airport Expressway.The measured data were used to analyze the interaction between the pile and soil of each pile under different loadings,the enhanced mechanism of pile-end post-grouting technique,and the bearing characteristics of pile foundation of the two different techniques.The research results showed that the vertical ultimate bearing capacity of the pile-end post-grouting piles increases by at least 40% and the settlement decreases by about 25 mm compared with that of the non-grouting piles,which suggested that the pile-end post-grouting technology can increase the bearing capacity and stability of pile foundation significantly.This paper proposed a calculation formula of the ultimate bearing capacity of a post-grouting single pile based on the observed data and grouting mechanism of pile-end post-grouting,which can provide valuable references for the pile foundation design in similar areas.