Evolution of the shear wave velocity during shaking modeled in centrifuge shaking table tests

• Published in: Bulletin of earthquake engineering Vol. 10; no. 2; pp. 401 - 420
• Main Authors: Lee, Chung-Jung, Wang, Chung-Ru, Wei, Yui-Chen, Hung, Wen-Yi
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.04.2012; Springer Nature B.V
• Subjects: Centrifuges; Civil Engineering; Earth and Environmental Science; Earth Sciences; Environmental Engineering/Biotechnology; Evolution; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Original Research Paper; Porosity; Sand; Seismic phenomena; Seismology; Shaking; Sound waves; Structural Geology; Water pressure; Bender elements; Shaking table tests; Shear wave velocity; Centrifuge modeling
• ISSN: 1570-761X; 1573-1456
• DOI: 10.1007/s10518-011-9314-y

Two in-flight shear wave velocity measurement systems were developed to perform the subsurface exploration of shear wave velocity in a centrifuge model. The bender elements test and the pre-shaking test used in the study provided reliable and consistent shear wave velocity profiles along the model depth before and after shaking in the centrifuge shaking table tests. In addition, the use of the bender elements measurement system particularly developed here allowed continuous examination of the evolution of shear wave velocity not only during and after the shaking periods in the small shaking events but also during the dissipation period of excess pore water pressure after liquefaction in the large shaking events. The test results showed that the shear wave velocity at different values of excess pore water pressure ratio varied as the effective mean stress to the power of 0.27, to a first approximation. Consequently, a relationship between the shear wave velocity evolution ratio and the excess pore water pressure ratio is proposed to evaluate the changes in shear wave velocity due to excess pore water generation and dissipation during shaking events. This relation will assist engineers in determining the shear stiffness reduction ratio at various r u levels when a sand deposit is subjected to different levels of earthquake shaking.