Sains Malaysiana 46(12)(2017): 2325–2329

http://dx.doi.org/10.17576/jsm-2017-4612-08

Pemodelan Geobencana Tanah Runtuh Rayap Menggunakan Model Analog Mekanik

(Geohazard Modelling of Creeping Landslide by Mechanical-Analogue Model)

NOR SHAHIDAH MOHD NAZER*

Geology Program, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan

Malaysia

Diserahkan: 12 April 2017/Diterima: 1 Jun 2017

ABSTRAK

Tanah runtuh jenis rayapan merupakan salah satu fenomena geobencana yang sering terjadi dalam skala yang besar dan amat berkait rapat dengan perubahan tekanan air liang. Ia bercirikan canggaan jangka masa panjang maka dengan itu pengetahuan mendalam terhadap tindak balas rayapan di dalam keadaan tepu dan tidak tepu air adalah penting untuk meramal pergerakan masa hadapan. Kertas ini bertujuan mengkaji tindak balas rayapan di dalam sampel lempung bebola menggunakan kotak ricih terus yang terubah suai. Simulasi rayapan dibuat menggunakan model analog mekanik hasil gabungan spring dan peredam. Parameter γo (pergerakan rayapan awal) yang diperoleh daripada ujian kotak ricih terubah suai digunakan sebagai input parameter bersama-sama dengan parameter lain yang diperoleh berdasarkan kaedah kuasa dua terkecil. Simulasi oleh model analog mekanik terhadap tindak balas rayapan yang direkod di makmal berjaya merakam tindak balas rayapan awal dan akhir. Keputusan kajian mendapati bahawa tindak balas rayapan adalah lebih signifikan di dalam keadaan tepu air berbanding keadaan tidak tepu air.

Kata kunci: Geobencana; lempung; model analog mekanik; rayapan; tanah runtuh

ABSTRACT

Creeping landslide is one of the big-scale geohazard phenomenon which closely related with changes in pore water pressure. It is characterized as long-term deformation; therefore, an in-depth knowledge of creep response under saturated and unsaturated condition is vital to project future movements. This paper examines creep response in Ball clay samples by means of modified direct shear box. Creep simulation was performed by mechanical-analogue model built upon springs and dashpots combinations. The parameter γo (initial creep movements) gained from modified direct shear box tests is used together with other parameters determined by the least-square method. Mechanical-analogue model simulations based on creep response recorded in the laboratory have successfully captured the initial and final creep response. The research finding showed that creep response was more significant under water-saturated conditions rather than unsaturated conditions.

Keywords: Creeping; geo-hazard; landslide; mechanical-analogue model

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*Pengarang untuk surat-menyurat; email: shahidahnazer@ukm.edu.my