As the geotechnical engineering profession moves forward into the twenty-first century, the role of seismic testing, as well as other geophysical testing methods, will increase. Geophysical methods present unique advantages, including a strong theoretical basis, the ability to perform the same basic measurement in the laboratory and field, and the noninvasive nature of many of the tests. A brief review of the fundamental concepts of seismic wave testing as applied in geotechnical engineering is presented. Determination of engineering design information (subsurface conditions and design parameters) is illustrated through case histories, which also highlight some of the strengths and inherent limitations of the methods. Suggestions for future directions, applications and potential developments are offered.
New demands in civil engineering require advanced characterization techniques to assess in-situ conditions and to monitor processes. Challenges include aging infrastructure, construction in critical/sensitive zones, restrictions created by the urban environment, trenchless construction, installation of new infrastructure, and environmental demands and protection. Near-surface geophysical methods can play a critical role in satisfying these needs. This situation resembles the role played by wave-based diagnostic technology in revolutionizing the medical practice during the 20th century, starting with X-ray plates and later including CAT-scan, PET-scan, ultrasound, and magnetic resonance imaging, among others. Geophysical methods (e.g., gravity, magnetic seismic and electromagnetic) offer the geotechnical/geoenvironmental engineer unique opportunities in characterizing sites, materials and processes. These opportunities arise from the strong theoretical bases upon which geophysical methods are founded, the complementary physical principles that support various field tests, and the ability to perform the same basic measurement in the laboratory and in the field. Furthermore, many geophysical methods are noninvasive; still, an image of the subsurface can be rendered from the tomographic reconstruction of boundary measurements. Finally, the increasing importance and future developments in this area are discussed.
