Abstract:
Subsurface exploration is one of the major activities conducted to extract
information for Geotechnical applications. Borehole construction is the most
common direct exploration technique which provides exact information on a
particular location whereas, Electrical Resistivity Method is one of the commonly
practiced indirect exploration techniques. Since the exploration costs are relatively
high, minimizing the cost while obtaining adequate information is of everyone’s
interest. For larger constructions with deep foundation requirements, determining
the overburden thickness (bedrock level) and water table is a mandatory
requirement. Hence, the use of a proper combination of direct and indirect
subsurface exploration methods could result a considerable cost reduction and time
saving. This study was conducted to find an optimum integration of resistivity
method and borehole construction for selected subsurface exploration activities
currently in progress. Accordingly, resistivity surveys were conducted at sites
proposed for a twelve storied residential tower at Malabe and Matara – Kataragama
Railway Extension Project, near piers for new railway track. Apparent resistivity
data were gathered using ABEM – Terrameter SAS 1000 instrument, were
interpretated using “IP 2 Win” software. The results were validated using the
borehole information. The resistivity survey information revealed a close
relationship with the borehole data and resides within the statistically acceptable
range. Hence, an optimum combination of resistivity surveying and borehole
construction can be proposed, for cost controlling at large-scale subsurface
explorations.
