Authors : Behnam Taghavi, Farnusch Hajizadeh and Mehdi Abbasi
Abstract: The resistivity method is one of the oldest geophysical survey techniques. The purpose of electrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the true resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters such as the mineral and fluid content, porosity and degree of water saturation in the rock. By evaluating the result shows that virtually every change in geoelectrical image coincides with a change in rock conditions and topsoil. The general trend was that high resistivity corresponded with good quality granit whereas low resistivity corresponds to poor quality rock, e.g., high weathering, low RQD, low Lugeon and/or low SPT and low lef for soil. The intermediate resistivity is often dolomite or rock with water bearing fractures. The study involved measuring VES at 144 locations in SW-NE direction and 124 in SE-NW direction using the Schlumberger array.
Behnam Taghavi, Farnusch Hajizadeh and Mehdi Abbasi, 2017. Geoelectrical Imaging Surveys used for Pre-Investigation and Subsurface Layers Modeling at a Water Transfer Tunnel (Case Study). Journal of Engineering and Applied Sciences, 12: 8409-8416.