Slope Failure Assessment In Penang Island Using Geoelectrical Methods
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Date
2018-04
Authors
Faharul Azman, Muhamad Iqbal Mubarak
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Slope failures never cease to end in hilly and slope area every year. This is very dangerous especially for those who lives within the proximity. However, slope is not only found in residential area but also alongside highways and federal roads. This research aims to investigate slope at the selected highly suspected area in Penang Island (Sungai Batu, Bukit Relau and Air Hitam) using 2D resistivity and induced polarization methods and to analyse and correlate the results from 2D resistivity method, induced polarization method, laboratory tests and rainfall distribution for slope failure potentials. The study areas were selected based on the previous studies and cases of slope failure reported in Penang Island. Based on the results, Sungai Batu has probability for slope failure due to weak zone with low resistivity value of 0 – 400 Ωm and low chargeability of < 3 ms while Bukit Relau was expected to have slope failure due to the weathering zone with intermediate resistivity 750 – 3000 Ωm and intermediate chargeability 3 – 10 ms. The existence of fractures also contributed to trigger the slope failures. Sungai Batu and Bukit Relau are located near faults and thus, intensified the slope failure potential due to highly jointed and sheared rocks characteristic. Air Hitam was determined to be vulnerable to slope failure due to the presence of clay saturated zone indicated by low resistivity value (< 400 Ωm) but high chargeability value (>25 ms). Soil laboratory tests were also conducted to determine the moisture content and porosity. The empirical correlation of resistivity and chargeability values obtained from geophysical methods with moisture content and porosity from soil laboratory tests indicated that they are inversely proportional to each other with strength of correlation range from strong to very strong.
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Keywords
Slope failure assessment in Penang Island , using geoelectrical methods