Kejadian tanah runtuh sudah menjadi suatu fenomena yang biasa dia kalangan rakyat
Malaysia, dengan kadar hujan yang sangat tinggi sepanjang tahun membuatkan ceruncerun
terdedah kepada kejadian tanah runtuh. Walaupun kejadian tanah runtuh sering
berlaku dan ia telah meragut ramai nyawa insan yang tidak berdosa. Justeru itu, kajian
yang terperinci perlu dilakukan bagi mengelak kehilangan nyawa orang awam dan juga
mengurangkan kos pembaikan semula yang telah rosak akibat kejadian tanah runtuh.
Kejadian ini dilakukan di Tanjung Bungah kerana permukaan bumi yang beralun dan
berbukit membuat ia sesuai dengan situasi kajian ini dan kebanyakan cerun-cerun ini
terdedah kepada kejadian tanah runtuh. Hujan adalah antara penyebab utama yang
menyebabkan kejadian tanah runtuh, apabila hujan berlaku air mula menyusup masuk
ke dalam tanah dan membuatkan cerun-cerun tersebut tidak stabil.
Kajian yang terperinci telah dijalankan bagi mencari faktor selamat bagi cerun-cerun
pada keadaan biasa manakala faktor selamat bagi keadaan di bawah faktor berbahaya
juga direkodkan. Umumnya, cerun berada tahap baik apabila faktor selamatnya dalam
lingkungan 1.5 sehingga 2.0 manakala cerun berada di tahap bahaya apa faktor
selamantnya di bawah lingkunga 1.5. Sehubungan itu, perhubungan paras air dalam
tanah dan hujan amatlah penting bagi mengenal pasti cerun-cerun yang di paras
berbahaya.
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Landslide is a phenomenon which is common thing in our country Malaysia, despite
having heavy rainfall throughout the year and make the slope or hilly area vulnerable
towards soil erosion and landslide hazardous. Even though is a common thing in here,
still it has kills many people and will be in the future. A comprehensive study need to
be done around the mountainous area so that people live can be save from landslide and
subsequently minimise the cost for repairing back the damage that had been done by
landslide.
This study has been conducted at Tanjung Bungah for it fits the situation for hilly area
and most of the slope are prone to landslide. Penang received a lot of rainfall density
due to monsoon. Therefore, rainfall has been known for primary force that caused
landslide occurrence, when rainfall seep through the soil it make the unsaturated soil
receive a lot of water and pore water pressure increase.
Thorough analysis has been carried out to find the factor of safety of existing slope and
factor of safety when water level at maximum level. The slope will be safe state when
factor of safety is higher than 1.5 to 2.0. Whereas, the slope is in critical or failure state
when the slope has been categorized below than 1.5. Therefore, the relationship
between water level and rainfall intensity is important to identify whether slope is
prone to landslide.
Effect ground water changes due to rainfall activity on slope at Tanjung Bungah, Penang / Ahmad Nabil Ismail