APPLICATION OF POST GROUTING IN BRIDGE FOUNDATION REINFORCEMENT: A CASE STUDY
The procedure of the post grouting technology that improved the ultimate bearing capacity of a pile in the ShunYi Bridge foundation was introduced in this paper. In situ static tests on two piles, pile #1 untreated by post grouting and pile #2 treated by post grouting, were conducted to obtain their ultimate bearing capacities. The ultimate bearing capacities were estimated based upon loading displacement curves using the Davisson offset limit load method, Chin Kondner method and China code method. The nominal resistance of pile #2 was calculated by the component multiplier approach, and the improvement coefficients of the soils for the four estimation methods were used to obtain its maximum, minimum and median nominal resistances. Numerical analysis of static tests was conducted to investigate the effects of the grouting location on the ultimate bearing capacity. The results showed that the post grouting technology improved the ultimate bearing capacity. The Davisson offset limit load method underestimated the ultimate bearing capacity of the treated pile, and the Chin Kondner method overestimated the ultimate bearing capacity. The nominal resistance of the treated pile depended on the improvement coefficients of the soils, which were calculated based on the in situ tests. Based on the numerical analysis, it is shown that the grouting location had a significant influence on the ultimate bearing capacity, and the ultimate bearing capacity increased if the grouting location is close to the pile tip.