摘要：The main objective of this paper is to evaluate the capabilities of the
nondestructive impact-response method in detecting the existence of defects
in long piles. The impact-echo technique, based on the use of transient
elastic waves, was developed many years ago for non-destructive detection of
defects in piles and structures. Moreover, is recognised in the specialised
literature that this method could be applied confidently for piles with
length/diameter relationship up to 20. However, with the development of hardware
in computers and new sensors and dynamic equipment, it is possible now to use
this method for long piles. In this paper, piles of length/diameter
relationship of approximately 40 are studied. A numerical-experimental
study was carried out. Finite element models 1D and 3D were performed for
piles including the surrounding soil and defects type necks and
bulbs. Subsequently, experimental studies were carried out to verify the
finite element models using similar piles. These experimental studies were
carried out in the air and soil, and impact responses were analyzed in both
time and frequency domains. It was shown that the results of the experiment
were in agreement with those of numerical studies, and the accuracy of
the impact-echo method was influenced by the type, size and location of
defects. In addition, it was also revealed that the method could be applied
for long piles.
