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As shown in the figure, a model test can simulate the type of deformation observed in the field such as
sliding, rotation, and settlement. In addition, during a centrifuge test, the transducers used (such as
accelerometers, pore pressure transducers, and LVDTs) can record in detail the dynamic response of the
soil and the wall, excess pore pressure generation in soil, and deformation process of the structure. Such
information is very helpful in the study of mechanism of response, in validating design calculations, and
in calibrating or verifying numerical analysis.
Numerical Modeling
For complex design situations such as a gravity wall with saturated backfill, comprehensive numerical
codes need to be used. In recent years, considerable progress has been made and several effective-stressbased-fully-coupled
programs have been developed. One of the challenges numerical simulation is facing
is how to verify the results of a numerical simulation. In the regards, physical modeling especially
centrifuge modeling has an important role to play. For example, as part of the VELACS project, the
response of the gravity wall shown in Fig. 2.1 during an earthquake was simulated using a computer
program SWANDYNE (Chang, 1989). The results are shown in Fig. 2.2 (Madabhushi and Zeng, 1998)
Fig, 2.2 Deformed finite element mesh after earthquake (unit: m)
The deformation simulated by the finite element program is similar to that recorded in the centrifuge test.
Thus, the code can be considered to have the ability to analyze complicated deformation of a gravity wall
with saturated backfill under earthquake loading.