Forensic assessment on near surface landslide using electrical resistivity imaging (ERI) at Kenyir lake area in Terengganu, Malaysia

• Main Authors: Mohd Hazreek, Zainal Abidin, Aziman, Madun, Saiful Azhar, Ahmad Tajudin, Mohd Fakhrurrazi, Ishak
• Format: Article
• Language: English
• Published: Elsevier Ltd 2017
• Subjects: TA Engineering (General). Civil engineering (General)
• Online Access: http://umpir.ump.edu.my/id/eprint/20672/7/Forensic%20Assessment%20on%20Near%20Surface%20Landslide.pdf; http://umpir.ump.edu.my/id/eprint/20672/; https://doi.org/10.1016/j.proeng.2017.01.354
• Institution: Universiti Malaysia Pahang

Electrical resistivity method which was championed by geophysicist has increasingly popular in civil engineering application due to its efficiency in term of cost, time and data coverage. In the past, conventional forensic assessment related to the landslide has experienced several limitations due to expensive, time consuming and limited data coverage. Hence, this study performed an alternative technique with particular reference to electrical resistivity imaging (ERI) in evaluating the slope failure at Kenyir Lake, Malaysia. During the data acquisition, two lines of ERI was performed using ABEM Terrameter LS set of equipment based on Schlumberger array. According to the ERI results produced, it was found that the subsurface profiles consist of completely weathered to highly weathered material (1 – 150 ohm.m), highly weathered to moderately weathered material (150 – 300 ohm.m), moderately weathered to hard material (300 – 2400 ohm.m) and fresh, hard and dry material (>2400 ohm.m). Moreover, electrical resistivity anomaly was managed to detect the presence of geological structure with particular reference to fault and rock discontinuities which associated to low resistivity anomaly. The heterogeneous of the subsurface material presented using integrated analysis of ERI and borehole data enabled forensic assessment of the landslide to be evaluated. The combination of heavy rainfall and existing geological structure (weakness zone) was believed to be a major factor which triggered this slope to be failed. This result was applicable to assist the geotechnical engineer in design concept recommendation of the slope remediation with fast, less cost and wide data coverage. Finally, ERI results with borehole verification was applicable to be adopted in landslide forensic assessment based on slope geomaterials stiffness variations generated after the slope movement. Furthermore, this electrical resistivity method adopts a surface technique that can minimize the disruption and damage to the site thus preserving a sustainable environment during the site data acquisition assessment.