Analytical Study of Employing Low-Strain Lateral Pile Integrity Test on a Defective Extended Pile Shaft

Abstract

The lateral pile integrity test (LPIT) method, a low-strain nondestructive test technique, is employed in this paper to evaluate the integrity of an extended pile shaft supporting superstructure. An extended pile shaft with various defects is simulated by a Timoshenko beam (TB) model, and the lateral soil resistance is generalized as a beam-on-dynamic-Winkler-foundation (BDWF) model. The pile–soil model and presented solution are verified by rigorous finite-element analysis (FEA). The effects of pile defect and technical aspects of the LPIT method on the pile dynamic response are then investigated, and a practical method is proposed as well to evaluate the potential defect of an extended pile shaft on site. By comparing the actual arrival time of the pile toe reflection with the calibration value, it is possible to determine the type (stiff or weak) and extent (length or total length) of the pile defect.