Evaluation of base grouting for the bearing behavior of barrette piles socketed in a gravel formation

Abstract

A comprehensive analysis for the effects of base grouting on barrette piles was carried out based on six compressive load tests on piles located in a newly developed residential area of the Taipei basin. All piles were socketed for a length of 3 m into a gravel formation at a depth of more than 45 m below the ground surface; four of these were base-grouted using the high-pressure cleaning and grouting method. Based on the strains measured at several depths along the pile shaft, side friction t–z curves for various soil strata and end bearing q–w curves in gravels are deduced. Comparing the test results of piles with and without base grouting, the effects of base grouting can be quantitatively evaluated. It is concluded that the base grouting has almost no influence on the initial stiffness of the pile head response curve for such a long piles, but significantly increases the ultimate bearing capacity and plastic stiffness of the pile head response curve for such long piles when they experience a large pile head displacement.