Static Testing of Pile-Base Post-Grouting Piles of the Suramadu Bridge

Pile-base post-grouting is a method in which solidifiable cement slurry is injected into the base of the pile through grouting pipes after the strength of the concrete reaches a certain value to strengthen the loose sediment at the hole base and the soil around the pile. The roles of grouting are to eliminate the influence of the technological defects of bored piles, to recover the bearing capacities of strata, and to improve the bearing capacities of piles. Pile-base post-grouting piles technology and Osterberg Cell load testing were applied to some test piles of the Suramadu Bridge. Based on test results of the bearing capacity, side frictional resistance, and base resistance of piles before and after grouting, post-grouting was found to have an obvious role in improving the quality, bearing capacity, and load transfer characteristics of the piles. An equation for calculating post-grouting piles under specific grouting conditions was obtained based on the statistical analysis of more than 50 test piles. The ranges of the improvement coefficients of side frictional and pile-base resistance for different soils are given. Key technologies and parameters of post-grouting are also suggested. The results of this research can be applied to designing bridge pile foundations, which may tap the bearing potential of the piles and result in notable economic benefits.