Application of Wave Propagation with Low Strain Pile Integrity Test—A Case Study

Abstract

Piles should possess the structural integrity to carry the design load and transfer to the soil/rock below. As per Indian standard IS 14893:2001, in general following defects are observed in the pile, which may lead to catastrophic failure. (a) Pile shaft necking, (b) Discontinuity of concrete, (c) Intrusion of foreign matter, (d)Improper toe formation due to contamination of concrete at the base with soil particles, (e) Washing of concrete due to high water current, and (f) Poor quality control with improper construction methods. NDT-based low strain pile integrity testing can be effectively used for evaluation of quality and acceptance of pile foundations. Low strain pile integrity test is based on pulse echo method. Pile integrity tester gives the velocity plot versus time. The plot is observed for the reflections, which indicate the change in the property of wave passing medium. The reflections may be due to soil resistance (stiffness) effects, cross-sectional changes, and soil property changes. In this study, bored cast-in-situ piles are evaluated for its integrity.