Sains Malaysiana 51(9)(2022): 3103-3112

http://doi.org/10.17576/jsm-2022-5109-29

Penilaian Cerun bagi Meramalkan Potensi Tanah Runtuh menggunakan Kaedah Sistem Penilaian Cerun Model-B di Empangan Sultan Mahmud, Tasik Kenyir, Kuala Berang, Terengganu, Semenanjung Malaysia

(Slope Assessment to Predict Landslide Potential using Model-B Slope Assessment System Method at Sultan Mahmud Dam, Kenyir Lake, Kuala Berang, Terengganu, Peninsular Malaysia)

MOHAMAD ANURI GHAZALI^1,* , MOHD ROZI UMOR² & ABDUL GHANI MD RAFEK²

¹Geo Mag Engineering, No 31B, Level 2, Jalan Pelabur B, 23/B, Seksyen 23, 40300 Shah Alam, Selangor Darul Ehsan, Malaysia

²Program Geologi, Jabatan Sains Bumi dan Alam Sekitar, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Received: 14 February 2022/Accepted: 21 June 2022

Abstrak

Penilaian geobahaya cerun telah dijalankan di Empangan Sultan Mahmud, Tasik Kenyir, Kuala Berang, Terengganu menggunakan kaedah Sistem Penilaian Cerun Model-B bertujuan untuk meramalkan potensi cerun mengalami tanah runtuh dengan nilai skor geobahaya. Kajian juga bertujuan untuk menilai ketepatan terhadap jenis cerun yang berbeza di ketiga-tiga kawasan kajian. Cerun di dalam kawasan kajian ini melibatkan cerun jenis potongan batuan, cerun potongan tanah dan cerun potongan batuan bercampur tanah. Terdapat 9 parameter yang diambil kira di dalam penilaian geobahaya iaitu sudut cerun, keluasan fitur, jarak dari permatang, bentuk cerun, peratusan fitur tak tertutup, kehadiran batuan terdedah, kehadiran saliran bertangga, kehadiran saliran mendatar dan kehadiran hakisan. Penilaian dijalankan di dalam batuan granit di kawasan berbukit iaitu di tiga tapak kajian iaitu tapak kajian 1, 2 dan 3 yang merangkumi keluasan 129 hektar. Hasil kajian di tapak kajian 1 mendapati skor geobahaya cerun batuan ini dikelaskan sebagai sangat tinggi dan tinggi. Faktor utama yang mempengaruhi skor geobahaya yang sangat tinggi dan tinggi adalah disebabkan sudut kecerunan yang tinggi dan keadaan batuan yang terdedah. Hasil kajian di tapak kajian 2 mengelaskan skor geobahaya adalah tinggi sahaja. Ini disebabkan oleh kecerunan yang tinggi, bentuk cerun, kewujudan hakisan dan tumbuhan tutup bumi. Manakala, hasil kajian di tapak 3 mendapati skor geobahaya adalah sederhana. Faktor utama yang menyebabkan skor geobahaya sederhana adalah kerana sebahagian merupakan cerun semula jadi, sudut kecerunan yang rendah, litupan tumbuhan pada cerun dan kehadiran hakisan yang rendah. Kesimpulan daripada kajian ini menunjukkan kaedah Sistem Penilaian Cerun Model-B (SPCM-B) adalah bersesuaian untuk digunakan dalam memetakan skor geobahaya bagi cerun jenis tanah potongan kejuruteraan.

Kata kunci: Geobahaya; Sistem Penilaian Cerun Model –B (SPCM-B); skor geobahaya

Abstract

Slope geohazard assessment were performed at Sultan Mahmud Dam, Tasik Kenyir, Kuala Berang, Terengganu using the Slope Assessment System method of Model-B. This study aims to predict slopes potentially experiencing landslides with geohazard score values. The study also aimed to evaluate the accuracy of this method on different slope types in the three study areas. The slopes in this study area involve rock cut type slopes, soil cut slopes and soil mixed rock cut slopes. There are 9 parameters taken into account in the geohazard assessment namely slope angle, feature area, distance from ridge, slope shape, percentage of uncovered features, presence of exposed rocks, presence of stair drainage, presence of horizontal drainage and presence of erosion. The assessment is generally carried out in granite rocks in hilly areas. There are three study sites named as study sites 1, 2, and 3 which cover an area of 129 hectares. The results of the study at study site 1 found that the geohazard scores of these rock slopes were classified as very high and high. The main factors influencing very high and high geohazard scores are due to high gradient angles and exposed rock conditions. The results of the study at study site 2 classifying the geohazard score were high only. This is due to high gradients, slope shapes, the presence of erosion and ground cover vegetation. Meanwhile, the results of the study at site 3 found that the geohazard score was moderate. The main factors that cause this moderate geohazard score are because part of the slope is natural, low slope angle, vegetation cover on the slope and low presence of erosion. The conclusion from this study shows that the Slope Assessment System method of Model-B is a very suitable method to be used in mapping the geohazard score for the slope of the engineering cut soil type.

Keywords: Geohazards; geohazards rating; Slope Assessment System Model B (SAS-B)

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^*Corresponding author; email: mohamadanuri16@gmail.com.my