Sains Malaysiana 54(7)(2025): 1657-1666

http://doi.org/10.17576/jsm-2025-5407-01

 

Systematic Approach to Boulder Stability Assessment at a Boulder Covered Area: Case Study at Gunung Bujang Melaka, Kampar, Perak

(Pendekatan Sistematik untuk Penilaian Kestabilan Tongkol di Kawasan Tongkol Tertutup: Kajian Kes di Gunung Bujang Melaka, Kampar, Perak)

 

TAN JIA QI¹, NORASIAH SULAIMAN¹, NOR SHAHIDAH MOHD NAZER¹, MUHAMMAD TAQIUDDIN ZAKARIA¹, NURUL ‘AMALINA MD NOR², ASKURY ABD KADIR, ABDUL GHANI RAFEK³, AILIE SOFYIANA SERASA¹, LEE KHAI ERN⁴ & GOH THIAN LAI^1,*

 

¹Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

²Jabatan Mineral dan Geosains Malaysia, Perak, Jalan Sultan Azlan Shah, 31400 Ipoh, Perak, Malaysia
³Engineering Geology Advisory, 11, SS21/12, Damansara Utama, 47400 Petaling Jaya, Selangor, Malaysia
⁴Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

Received: 6 December 2024/Accepted: 26 May 2025

 

Abstract

Gunung Bujang Melaka is set to be developed into a tourist attraction, prompting a study of the granite boulders in the area to ensure visitor safety. This paper aimed to identify potential unstable boulders and produce a stability zonation map of the designated area. Aerial photogrammetry was conducted to create a 3D model of the project area, capturing the boulders' characteristics. Each boulder was delineated using 3D processing software-ShapeMetrix-to acquire dimensions, base dipping angles, and azimuths. The general slope angle of the project area was generated using the moving average grid method on the digital elevation model (DEM) produced from the 3D model. Tilt tests were performed on-site, showing a basic frictional angle of 30° and a peak frictional angle of 66°. Over 1,600 boulders were identified across the area, with 274 boulders having visible base angles evaluated using kinematic analysis and the Hoek & Bray block model for stability assessment. The results indicated five types of boulder stability: Exceptionally Stable (8, 3%), Very Stable (102, 37%), Stable (16, 6%), Likely Stable (126, 46%) and Potential Sliding (22, 8%). The remaining boulders, with their base planes concealed by surrounding boulders, were considered interlocking due to deep-seated and support from adjacent boulders. Mitigation measures such as bracing and anchoring are recommended based on their modes of failure.

Keywords: Boulder stability; drone photography; GIS processing; Hoek and Bray; kinematic analysis

 

Abstrak

Gunung Bujang Melaka yang akan dibangunkan sebagai tarikan pelancongan mencetuskan kajian terhadap tongkol granit di kawasan ini bagi memastikan keselamatan pelawat. Kajian ini bertujuan mengenalpasti kestabilan tongkol dan menghasilkan peta zonasi kestabilan untuk kawasan tersebut. Fotogrametri udara telah dijalankan untuk menghasilkan model 3D kawasan kajian bagi mencirikan setiap tongkol yang sedia ada. Setiap tongkol dilakarkan dengan penggunaan perisian pemprosesan 3D ShapeMetrix untuk memperoleh dimensi, sudut tapak dan arah kemiringan tongkol. Sudut cerun umum kawasan projek dijana menggunakan kaedah Moving Average atas Digital Elevation Model (DEM) yang dihasilkan daripada model 3D. Ujian kemiringan yang dijalankan menunjukkan sudut geseran asas adalah sebanyak 30° dan sudut geseran puncak adalah sebanyak 66°. Lebih daripada 1,600 bongkah telah dikenalpastikan di dalam kawasan kajian dan hanya 274 bongkah yang mempunyai tapak tongkol yang boleh dinilai maka dapat menggunakan analisis kinematik dan model blok Hoek & Bray untuk penilaian kestabilan mereka. Hasil tersebut mengelaskan kestabilan bongkah kepada lima kategori iaitu paling stabil (8 bongkah, 3%), sangat stabil(102 bongkah, 37%), stabil (16 bongkah, 6%), kemungkinan stabil (126 bongkah, 46%) dan berpotensi gelinciran (22 bongkah, 8%). Tongkol-tongkol yang mempunyai tapak kemiringan yang tersembunyi oleh tongkol sekeliling adalah dikelaskan kepada saling pancaan disebabkan kedudukan yan mendalam serta sokongan daripada bongkah bersebelahan. Langkah mitigasi seperti pendakap dan sauh dicadangkan berdasarkan mod kegagalan masing masing.

Kata kunci: Analisis kinematik; fotografi dron; Hoek dan Bray; kestabilan batu; pemprosesan GIS

 

REFERENCES

Alejano, L.R. & Carranza-Torres, C. 2011. An empirical approach for estimating shear strength of decomposed granites in Galicia, Spain. Engineering Geology 120(1-4): 91-102. https://doi.org/10.1016/j.enggeo.2011.04.003

Alejano, L.R., Pérez-Rey, I., Muñiz Menéndez, M., Riquelme, A. & Walton, G. 2022. Considerations relevant to the stability of granite boulders. Rock Mechanics and Rock Engineering 55: 2729-2745. 10.1007/s00603-021-02525-9

Alejano, L.R., Muralha, J., Ulusay, R., Li, C.C., Pérez-Rey, I., Karakul, H., Chryssanthakis, P., Aydan, Ö., Martínez, J. & Zhang, N. 2017. A benchmark experiment to assess factors affecting tilt test results for sawcut rock surfaces. Rock Mech. Rock Eng. 50(9): 2547-2562

Alejano, L.R., Ordóñez, C., Armesto, J. & Rivas, T. 2010. Assessment of the instability hazard of a granite boulder. Nat. Hazards 53: 77-95. https://doi.org/10.1007/s11069-009-9413-0

Armesto, J., Ordóñez, C., Alejano, L. & Arias, P. 2009. Terrestrial laser scanning used to determine the geometry of a granite boulder for stability analysis purposes. Geomorphology 106(3-4): 271-277. https://doi.org/10.1016/j.geomorph.2008.11.005

Barton, N. & Choubey, V. 1977. The shear strength of rock joints in theory and practice. Rock Mechanics 10: 1-54. 10.1007/BF01261801

Goh, T.L., Ghani Rafek, A. & Hariri Arifin, M. 2014. Correlation of joint roughness coefficient with peak friction angles of discontinuity planes of granite, Peninsular Malaysia. Sains Malaysiana 43(5): 751-756.

Hoek, E. & Bray, J. 1977. Rock Slope Engineering, 1st ed. London: IMM.

Hutchison, C.S. & Tan, D.N.K. 2009. Geology of Peninsular Malaysia. Kuala Lumpur: University of Malaya and Geological Society of Malaysia.

Migon´, P. 2006. Geomorphological Landscapes of the World. Springer Dordrecht.

Pérez-Rey, I., Alejano, L.R., Riquelme, A. & González-deSantos, L. 2019. Failure mechanisms and stability analyses of granitic boulders focusing a case study in Galicia (Spain). International Journal of Rock Mechanics and Mining Sciences 119: 58-71. https://doi.org/10.1016/j.ijrmms.2019.04.009

Vann, J., Olaiz, A.H. & Zapata, C. 2019. A practical approach to a reliability-based stability evaluation of precariously balanced granite boulders. 53rd US Rock Mechanics/Geomechanics Symposium, Brooklyn, New York.

Wyllie, D.C. & Mah, C.W. 2005. Rock Slope Engineering: Civil and Mining. 4th ed. London: Spon Press.

 

*Corresponding author; email: gdsbgoh@gmail.com