Enhancement of drilled piles with combined tip and shaft grouting – A case study

In this study static load testing of three full scale drilled piles with combined tip and shaft grouting was conducted, where pile head load, pile head settlement, and compression strain of the piles were recorded. It was found that post-grouting tip and shaft of drilled piles can increase pile capacity significantly. Strain incompatibility existed between side friction and tip bearing of the post-grouted piles as the side friction was mobilized before the tip bearing was activated and the piles failed due to the plunge failure before the side friction reached the ultimate strength. It is found that the side shear enhancement of the same type soil varied based on the depth of the soil layer and decreased from pile head toward the tip of piles. The experimental program and theoretical analysis are presented in this paper.