Application Of Surface Wave And Geoelectrical Resistivity Methods In Geotechnical Site Investigation
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Date
2013-07
Authors
Khaizal
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Many cases of constructions failure have been reported and the prohibitive
cost of investigation has also increased due to the unavailability of subsurface
information. The physical and mechanical behaviours of geological materials are
commonly unpredictable. Lately conventional methods that include: drilling, cone
penetration test (CPT), vane shear test, standard penetration test (SPT) have long
been directly used in geotechnical site investigation for civil engineering purpose.
Yet, in its implementation these methods required more cost compared to the total
cost of construction project. Commonly three to five boreholes only, which
geotechnical engineers using extrapolate method of boreholes to cover entirely site
area. Advanced geophysical technologies are capable of solving these problems.
These methods are relative more cost-effective, fast, non invasive and more robust of
data acquired. Geophysical methods of surface wave and geo-electrical resistivity
imaging methods were carried out at three investigation sites: Merbok Kedah, Balik
Pulau and Nibong Tebal Pulau Pinang in Peninsular Malaysia. Continuous fixed roll
along method was implemented for two dimensional surface wave field data
acquisition. A Wenner-Schlumberger array was selected for geo-electrical resistivity
imaging. The results of the study at the three sites showed that for Merbok site, the
geophysical methods have successfully delineated residual soil over bedrocks and
successfully detected marine sediments over weathered granitic bedrocks at Balik
Pulau site as well as also reasonable results of detected low velocity zone at Nibong
Tebal site. Drilling of two boreholes which include SPT test were conducted in each
of the sites. Comparisons of shear wave velocity and geo-electrical resistivity-value
with boreholes data showed good agreement and consistence. Although, geophysical
methods showed good results, borehole data even in minimum quantities are still
needed in the geotechnical engineering site investigation. The results of the study
show that the application of surface wave and geo-electrical resistivity methods can
be complement of conventional methods and in turn reduce the cost of site
investigation.
Description
Keywords
Physical and mechanical behaviours of , geological materials