Sains Malaysiana 48(11)(2019): 2493–2501

http://dx.doi.org/10.17576/jsm-2019-4811-19

Integrated Cave Stability Assessment: A Case Study at Naga Mas Cave, Mount Pua, Kinta Valley, Ipoh, Perak, Malaysia

(Penilaian Kestabilan Gua Integrasi: Kajian Kes di Gua Naga Mas, Bukit Pua, Lembah Kinta, Ipoh, Perak, Malaysia)

GOH THIAN LAI¹*, LOK KAH KIT¹, AZIMAH HUSSIN¹, AILIE SOFYIANA SERASA², ABDUL GHANI RAFEK³, LEE KHAI ERN⁴, TUAN RUSLI MOHAMED⁵, SHAO LEI⁶, YANLONG CHEN⁷ & MINGWEI ZHANG⁷

¹Centre for Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

²School of Engineering, Asia Pacific University of Technology and Innovation (APU), Technology Park Malaysia, 57000 Bukit Jalil, Kuala Lumpur, Federal Territory, Malaysia

³Engineering Geology Advisory, 11, SS21/12, Damansara Utama, 47400 Petaling Jaya, Selangor Darul Ehsan, Malaysia

⁴Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

⁵Jabatan Mineral dan Geosains Malaysia, Menara PJH, Tingkat 9 Jalan Tun Abdul Razak, Presint 2, 62000 Putrajaya, Malaysia

⁶School of Ocean and Earth Science, Tongji University, Shanghai, China

⁷State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China

Received: 13 March 2019/Accepted: 15 August 2019

ABSTRACT

Naga Mas Cave, a natural cave which also houses a temple is becoming one of the popular places of worship for Buddhist community in Ipoh, Perak. With the increasing number of worshippers entering the cave, the stability of this cave becomes important. With that in mind, an assessment on natural cave stability was conducted in the interest of public safety. Slope Mass Rating (SMR), Q rock mass classification system and cave roof thickness-width ratio of cave were employed in this assessment. The lithology of study area consists of dolomitic limestone. Discontinuity surveys were conducted at two slopes, labeled C1 and C2. For slope C1, three (3) joint sets J1, J2 and J3 with the dip direction and angles of 332º/49º, 154º/37º and 049º/80º, respectively, were identified. While slope C2 has four (4) sets of joints J1, J2, J3 and J4 with the dip direction and angles of 323º/44º, 125º/57º, 42º/76º, 263º/67º, respectively. The relationship between the rock quality, Q values and cave width shows that all parts inside the cave need support except for the cave chamber at the northern part. As for the cave wall stability, the northern part of the south east wall, south eastern and southern part as well as the north western wall and south western corner were classified as poor slope class due to the unfavorable orientation of the cave wall. Ratio of cave roof thickness and cave width shows that the cave is stable. From the results, a mitigation plan is proposed to highlight the cave safety zone to ensure the safety of worshippers and public visiting the cave.

Keywords: Cave roof thickness; cave stability; mitigation; Q-system; Slope Mass Rating (SMR)

ABSTRAK

Gua Naga Mas, sebuah gua semula jadi yang juga menempatkan sebuah kuil telah menjadi salah satu tempat ibadat popular bagi masyarakat Buddha di Ipoh, Perak. Dengan semakin banyak penganut agama Buddha memasuki gua, tahap kestabilan gua ini menjadi penting. Dengan itu, satu penilaian terhadap kestabilan gua semula jadi dilakukan demi kepentingan keselamatan awam. Perkadaran Jasad Cerun (SMR), sistem pengelasan jasad batuan Q dan nisbah ketebalan bumbung-lebar gua telah digunakan dalam penilaian ini. Litologi kawasan kajian terdiri daripada batu kapur dolomit. Tinjauan ketakselanjaran dijalankan pada dua cerun, yang dilabelkan C1 dan C2. Untuk cerun C1, tiga (3) set kekar J1, J2 dan J3 dengan arah kemiringan dan sudut kemiringan iaitu masing-masing 332º / 49º, 154º / 37º dan 049º / 80º telah dikenal pasti. Manakala cerun C2 mempunyai empat (4) set kekar J1, J2, J3 dan J4 dengan arah kemiringan dan sudut kemiringan sebanyak masing-masing 323º / 44º, 125º / 57º, 42º / 76º, 263º / 67º. Hubungan antara kualiti jasad batuan, nilai Q dan lebar gua menunjukkan bahawa semua bahagian di dalam gua memerlukan sokongan kecuali ruang gua di bahagian utara. Bagi kestabilan dinding gua, bahagian utara dinding tenggara, bahagian tenggara dan selatan serta dinding barat laut dan bahagian barat daya dikelaskan sebagai kelas cerun tidak baik disebabkan oleh orientasi dinding gua yang kurang baik. Nisbah ketebalan bumbung gua berbanding dengan lebar gua menunjukkan bahawa gua dalam keadaan stabil. Daripada hasil kajian ini, satu pelan mitigasi telah dicadangkan untuk menyorotkan zon keselamatan gua untuk memastikan keselamatan para penganut dan orang awam yang mengunjungi gua tersebut.

Kata kunci: Kestabilan gua; ketebalan bumbung gua; mitigasi; Perkadaran Jasad Batuan (SMR); Sistem-Q

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*Corresponding author; email: gdsbgoh@gmail.com