KY Wong, L&M Geotechnic Sdn Bhd, Malaysisa, formerly department of civil engineering, University of Queensland, Australia. This paper was first published in GE’s November 1995 edition.
The interpretation of small strain sonic pile tests requires a proper understanding of the mechanics of stress wave propagation, rational judgement and the need to account for both soil condition and construction method. Without proper account of these factors, the interpretation can be misleading.
This paper presents results from laboratory experiments and field tests on piles using the small strain sonic method to detect changes in pile sections. In the laboratory, members with predetermined sectional changes were tested before and after installation in soil which had been improved with cement stabilisation at certain locations. These results indicate the difficulty associated with interpretation of data from such tests.
Field measurements were carried out on rammed Frankipiles, and the results show that misinterpretation can also easily result if no account is taken of the soil condition and construction technique.