SASW test in location of buried objects
- Rutgers Univ., Piscatway, NJ (United States)
The ability to detect underground objects is of significant importance in certain aspects of civil (geotechnical) and environmental engineering. A number of geophysical techniques have shown excellent results in location of certain types underground obstacles (anomalies). The Spectral-Analysis-of-Surface-Waves (SASW) method is a seismic nondestructive technique, that has so far been typically used in the evaluation of elastic moduli and layer thicknesses of layered systems, like soils and pavements. One of the assumptions of the test is that the system tested consists of infinite homogeneous layers of a constant thickness. This assumption is violated whenever heterogeneity of the system exists due presence of buried objects and cavities, presence of discontinuities, like pavement edges, variation of layer thicknesses, etc. The problem is of special importance in SASW testing of pavements in an urban environment, where obstacles like utility conduits, subways, and foundation structures cause wave reflections that can affect significantly test results. The effects of anomalies on propagation of elastic waves have been examined by a number of authors. On the other hand, Haupt, Dravinsky and Curro demonstrated numerically and experimentally that surface waves are sensitive to anomalies close to the surface. Recently Al-Shayea demonstrated experimentally that results of the SASW test are affected by underground objects. They showed that an underground cavity artificially created in a homogeneous sand layer can cause significant decrease in the phase velocity of the Rayleigh wave in a broad frequency range. Later, numerical simulations by Gucunski confirmed findings of Al-Shayea. The following paragraphs discuss the most important findings on the effects of underground obstacles on the Rayleigh wave dispersion obtained from the SASW test, and the application of the test in detection of buried objects.
- OSTI ID:
- 381495
- Report Number(s):
- CONF-960477-; TRN: 96:004278-0029
- Resource Relation:
- Conference: 9. annual symposium on the application of geophysics to engineering and environmental problems, Denver, CO (United States), 15 Apr - 1 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of SAGEEP `96: Proceedings of the symposium on the application of geophysics to engineering and environmental problems; Bell, R.S.; Cramer, M.H. [comps.]; PB: 1353 p.
- Country of Publication:
- United States
- Language:
- English
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