The 2D electrical resistivity tomography (ERT) study for civil and geotechnical engineering purposes

Abstract

2-D electrical resistivity tomography (ERT) is one of the geophysical methods applied in subsurface study for engineering purposes. The ERT result was correlated with 2 boreholes to identify the subsurface characteristic. The study location situated at PT 8088 and 8089, Rawang, Selangor, Malaysia with coordinate of 3 15 37.2 N and 101 38’ 48.22. Four ERT survey lines were conducted at the study area with Pole-dipole array with 5m minimum electrode spacing, 5mA and 20mA of minimum and maximum d.c. current respectively. The ERT results show the study area consists of two main zones, alluvium with resistivity value of 10-800 m, and granite bedrock with resistivity value of >2500 m with depth 5-70m. Saturated zone and hard layer were detected with resistivity value of <110 m and 1500-2500 m respectively which indication of fractured zone. Borehole record, BH3 and BH5 show the overburden was alluvium (gravels with sand) and depth to granite bedrock was 25.5m and 12.0m respectively.