Analysis of Strain-gage Records from a Static Loading Test on a CFA Pile

Abstract

A static test was performed on a 610-mm diameter, 10 m long CFA pile installed through 3 m of clay and sand and into a thick deposit of lacustrine clay. The loading procedure included prolonged load-holding and an unloading-reloading event, which adversely affected the interpretations of the strain records and demonstrated the inadvisability of not performing a test with equal load-increments and equal load-holding durations and avoiding all unloading-reloading sequences. The pile was strain-gage instrumented at three levels and the recorded strains were used to calculate the pile axial stiffness and determine the load distributions for the applied load. Back-calculations using effective stress analysis were fitted to strain-gage determined load distributions and were then used in simulating the measured pile-head load-movement of the test pile.