Field test research on post-grouting effect for super-long cast-in-place bored pile in thick soft foundation

Abstract

The field static load test method was adopted for two test piles in a project in Zhejiang area of China, analyze the effect of post-grouting technique on super-long cast-in-place bored pile and its internal mechanism. Q-s curves and pile axial force curves were drawn based on test data to show that post-grouting technique played a prominent role in improving bearing capacity of single pile and pile skin friction. In addition, pile skin friction at upper soil layer around super-long pile was fully used, but that at lower soil layer was not. For the design of super-long pile, the compression of pile body should be considered to make the best use of pile skin friction caused by relative displacement between pile and soil.