Effects of the Source on Wave Propagation in Pile Integrity Testing
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 136, Issue 9
Abstract
One-dimensional stress wave theory is widely used to analyze quantitatively the reflections in low-strain integrity testing of piles. However, a point or disk loading produces body and Rayleigh waves near the pile top. The multireflections of these waves from the lateral surface of a pile are present in the wave field near the pile top. Effects of three-dimensional waves on the near field responses are obvious. These effects can be interpreted erroneously by an inexperienced user as “noises” or “pile anomalies.” To investigate wave propagation in the longitudinal direction, the behavior of the waves in the far field (some distance below the pile top) is studied by theoretical analysis of the longitudinal modes in free cylinders and numerical simulations. The wave pattern at the pile top is analyzed based on the response of an elastic half-space to a harmonic disk loading. The results show that when the ratio of the characteristic length of an impact pulse to the cylinder radius is large enough, the components of Rayleigh waves in the wave field at the pile top are diminished; the waves in the far field behave approximately as plane waves; the responses at positions between and from the pile axis are less affected by the multireflections. The results from numerical simulations support the practical recommendation to use a ratio of characteristic wavelength to pile radius larger than four. Under this condition, the reflections from the far field (say deeper than two pile diameters) can be analyzed from the responses at receiver positions about from the pile axis based on one-dimensional stress wave theory.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
Comments from anonymous reviewers are highly appreciated and they have greatly improved the clarity of this paper.
References
Chao, H. C. (2002). “An experimental model for non-destructive evaluation on pile foundations using guided wave approach.” Ph.D. dissertation, Northwestern Univ., Evanston, Ill.
Chen, F., and Wang, R. J. (1998). “Dimensional effects on low strain integrity testing of piles.” Chinese J. Geotech. Eng., 20(5), 92–96 (in Chinese).
Chow, Y. K., Phoon, K. K., Chow, W. F., and Wong, K. Y. (2003). “Low strain integrity testing of piles: Three dimensional effects.” J. Geotech. Geoenviron. Eng., 129(11), 1057–1062.
Foinquinos, R., and Roësset, J. M. (2001). “Elastic layered half-space subjected to dynamic surface loads.” Wave motion in earthquake engineering, E. Kausel and G. Manolis, eds., WIT Press, Southampton, U.K.
Graff, K. F. (1975). Wave motion in elastic solids, Ohio State University Press, Ohio.
Hanifah, A. A. (1999). “A theoretical evaluation of guided waves in deep foundation.” Ph.D. dissertation, Northwestern Univ., Evanston, Ill.
Liao, S. T., and Roesset, J. M. (1997a). “Dynamic response of intact piles to impulse loads.” Int. J. Numer. Analyt. Meth. Geomech., 21, 255–275.
Liao, S. T., and Roesset, J. M. (1997b). “Identification of defects in piles through dynamic testing.” Int. J. Numer. Anal. Methods Geomech., 21, 277–291.
Middendorp, P., and Reiding, F. J. (1988). “Determination of discontinuities in piles by TNO integrity testing and signal matching technique.” Proc., 3rd Int. Conf. on the Application of Stress Wave Theory to Piles, BiTech, Vancouver, 33–43.
Pavlakovic, B. N. (1998). “Leaky guided ultrasonic waves in NDT.” Ph.D. thesis, Imperial College Science, Technology and Medicine, Univ. of London, London.
Rausche, F., Likins, G. E., and Shen, R. K. (1992). “Pile integrity testing and analysis.” Proc., 4th Int. Conf. on the Application of Stress Wave Theory to Piles, Balkema, Rotterdam, The Netherlands, 613–617.
Seidel, J. P., and Tan, S. K. (2004a). “Elimination of the Rayleigh wave effect on low strain integrity test results (part 1: Experimental investigation).” Proc., 7th Int. Conf. on the Application of Stress Wave Theory to Piles, Institution of Engineers Malaysia, Petaling Jeya, Malaysia, 179–185.
Seidel, J. P., and Tan, S. K. (2004b). “Elimination of the Rayleigh wave effect on low strain integrity test results (part 2: Rayleigh wave elimination technique).” Proc., 7th Int. Conf. on the Application of Stress Wave Theory to Piles, Institution of Engineers Malaysia, Petaling Jeya, Malaysia, 187–192.
Starke, W. F., and Janes, M. C. (1988). “Accuracy and reliability of low strain integrity testing.” Proc., 3rd Int. Conf. on the Application of Stress Wave Theory to Piles, BiTech, Vancouver, 19–32.
Information & Authors
Information
Published In
Copyright
© 2010 ASCE.
History
Received: Jan 30, 2009
Accepted: Oct 22, 2009
Published online: Aug 13, 2010
Published in print: Sep 2010
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.