Lotung Downhole Array: Evaluation of Soil Nonlinear Properties
M. Zeghal*, Associate Member ASCE,
A.-W. Elgamal*, Member ASCE,
H. T. Tang*, and
J. C. Stepp*
Abstract:
The characteristics of soil response during earthquake excitations,
at a site in Lotung, Taiwan are identified using the Lotung Large
Scale Seismic Test (LSST) data. A technique is developed to evaluate
soil shear stress-strain histories directly from the free-field
downhole accelerations. These histories are used to: i)
estimate variation of soil shear moduli and material damping
characteristics with shear strain amplitude, and ii) assess
the effects of pore pressure buildup. Soil stiffness properties are
found to compare satisfactorily with those obtainedthrough laboratory
tests conducted by the University of California at Davis, the National
Taiwan University and the University of Texas at Austin. Pore pressure
buildup appears to be accompanied by a reduction in soil stiffness.The
information obtained in this study demonstrates that downhole
accelerometerand pore pressure arrays offer a direct effective means
of evaluating seismic soil properties.
For Questions or Comments:
zegham@rpi.edu
elgamal@rpi.edu
