About the presentation
"Subsurface Imaging of Ground Conditions for Engineering Applications"
New demands in civil engineering require advanced characterization techniques to assess in-place conditions and to monitor processes. The geotechnical engineering branch of civil engineering is faced with the problem of characterizing near-surface soil and rock deposits. The near-surface region is often within 10 to 100 m of the ground surface. Traditional geotechnical exploration programs have involved boring, sampling, and penetration testing to characterize the material in place. These exploration programs are time consuming and expensive. In the past 15 years, stress wave (seismic) measurement techniques using surface waves have been developed for this purpose. One of the key benefits of surface-wave techniques is that they are non-invasive: No borings in the soil or rock deposits are required. Therefore, field testing is rapid and cost effective when compared with traditional geotechnical exploration programs. Surface wave measurements permit vertical profiles of the shear stiffness to be evaluated from which images of the subsurface are developed. Shear stiffness profiles and images are used to predict deformations at the ground surface and within the geotechnical system due to static and dynamic loads. Several case histories are presented to demonstrate one surface-wave measurement technique, including a comprehensive field investigation at the proposed location of the high-level radioactive waste repository at Yucca Mountain, Nevada.
|
