An Investigation of Buried Metal Object in High Electrical Conductivity Soil Layer Using Electrical Resistivity Survey Method

Abstract

This study presents an investigation of buried metal object in Bangkok soft clay which has high electrical conductivity using electrical resistivity imaging (EI) as aimed to be applied for an application of underground infrastructures investigation planning and development such as gas pipeline, water line, or other buried metal objects. However, the electrical resistivity survey method has the best performance when applied over resistive terrain. This study, a metal cube about the size of 1 x 1 x 1 m was buried at 0.5 m-depth in the Bangkok soft clay ground. Afterward, 3D electrical resistivity imaging using pole-pole electrode configuration and 2D electrical resistivity imaging using Wenner electrode configuration had been performed to investigate a buried metal cube. The initial investigation result, 3D resistivity result hard to indicate buried metal object as it presents unclear shape. Next, the electrical wire was connected from buried object to the positive pole of the 12 v battery as aimed to make a contrast of electrical properties between the metal object and soft clay media. The final 3D resistivity result indicates the shape and position of buried metal more correctly. 2D resistivity imaging result at the initial stage indicates no buried metal object. After the buried metal object was connected to the battery, it has clearly identified in the 2D resistivity result.