Estimation of Dynamic and Liquefaction Properties by Shear Wave Velocity
Date
2009
Authors
Gautam, Suman
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Geology
Abstract
The analysis of foundation vibrations and geotechnical earthquake engineering
problems in civil engineering requires characterization of dynamic soil properties
using geophysical methods. Dynamic structural analysis of the superstructures
also requires knowledge of the dynamic response of the soilstructure, which in
turn relies on dynamic soil properties. Geophysical methods are often used to
characterize the dynamic soil properties of the subsurface. This method requires
a borehole through which a sensing probe is lowered at known level. Source near
the borehole is generated artificially with the help of wooden plank and hammer.
The seismogram obtained from computer aided system is used to determine shear
wave velocity and compressive wave velocity which is further used to calculate
dynamic parameters such as Poisson’s ratio, dynamic shear modulus, dynamic
elastic modulus and predominant period etc. Ground water table is very close to
ground surface and the soil is mainly fine to coarse sand with some intermittent
layers of cohesive soils meaning that the soil is very liable to liquefaction.
Liquefaction resistance is assessed in terms of cyclic stress ratio and in terms of
factor of safety both of which show that the liquefaction potential of the site is
very high mainly near shallow depth less than 10m.
Description
Keywords
Shear wave velocity, Predominant period, Cyclic stress ratio, Soil liquefaction