Slope Failure Investigation in Weathered Granitic Rock Mass Using Electrical Resistivity Imaging: Case Study in Kg Bukit Selar, Jeli, Kelantan, Malaysia

Abstract

The slope failure phenomenon is a common natural hazard in Malaysia in which due to the change in slope angle, weathering, heavy rainfall, and overloading. This research is focusing on analyzing the subsurface condition of slope failure in Kg Bukit Selar, Jeli, Kelantan by the electrical resistivity imaging (ERI) method. Geologically, the study area mainly composed of granitic rocks (microgranite and porphyritic granite). A total of five resistivity survey lines using Schlumberger and Pole-Dipole array with a 200m spread was conducted at the failed slope. ABEM Terrameter LS was used to collect field data, and processed by using RES2DINV software. The results were presented in the form of two-dimensional (2D) resistivity profiles providing a view of the subsurface distribution of the granitic rock, geological structures, and water content. The results show that the slope failed due to the presence of groundwater. The findings in this study show that the resistivity survey is a reliable method for slope failure investigation. The slope failures due to seepage problems were successfully being investigated using the ERI method.