GROUND INVESTIGATION USING 2D RESISTIVITY IMAGING FOR ROAD CONSTRUCTION

Abstract

This paper présents finding on the ground exploration using 2D resistivity imaging. The study was conducted to verify the borehole result, which shows a conflict between the actual site conditions. The proposed study is to investigate of high topography area for road construction. Electrical resistivity imaging method was used for estimating bedrock at Bandar Sri Sendayan, Negeri Sembilan. The site consist of acid intrusive igneous, which is dominantly covered by granite. Two lines of resistivity survey were conducted to identify ground material of this area. The survey was conducted using ABEM Terrameter equipment, where a two-dimensional resistivity profile has been identified for ground exploration and subsurface profiling. The resistivity images showed the existence of boulders and bedrock in multiple weathering grades with resistivity values ranges from 50 to 10 000 ohm-m along the proposed road alignment. The presence of these boulders and weathered bedrock probably not suitable to be used as domestic supply for road material such as crushed aggregate especially at depth less than 30m from surface. Soil or overburden was discovered 12m from the surface. The finding shows the mismatched between the borehole result and resistivity profile, where the borehole data was interpreted as bedrock however the resistivity result proved that it is a boulder.