The Investigation of Risk Assessment of Rock Slopes Considering the Socioeconomic Loss due to Rock Fall.

The construction of the Tugu Dam spillway does not escape the problem of slope instability, especially the rock fall type landslide as a result of the rock slope cutting work at STA+80. The purpose of this study was to determine the characteristics of the rock discontinuity area and the solutions needed to address the potential hazards of rock fall on the slopes of spillway structure. In this study, a semi-quantitative method conducted based on the Rockfall Hazard Rating System (RHRS) which is carried out by identifying outcrops on rock slopes. Determination of the rock fall trajectory, was conducted by statistical methods on rock mass based on changes in velocity when rocks roll, slide, and bounce. Geologically, the research area belongs to the Mandalika Formation. Based on the RHRS weighting, the total score on the STA+80 slope is 399, which means that the slope needs to be repaired or given safely with a moderate level of urgency. The rock fall trajectory modeling at the measurement location X = 121,875 has a kinetic energy of 973.14 kJ andesite and 72.59 kJ of volcanic breccia, for high results of 0.43 meters of andesite reflection and 2.04 meters of volcanic breccia, and velocity results translational velocity obtained at 33.8 m/s andesite and 8.67 m/s volcanic breccia. The potential for rock fall requires a safety system with a type of retained flexible barriers with a height of 5 meters that can be applied to the toe of the slope.Keywords: rock fall, discontinuity, trajectory, protection system, Tugu Dam

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Leveraging on Multidisciplinary Expertise for Landslide Disaster Risk Reduction and Management: A Case Study of a Limestone Hill Rockfall Hazard Assessment, Batu Caves, Selangor, Malaysia

Sains Malaysiana ◽

10.17576/jsm-2021-5008-04 ◽

2021 ◽

Vol 50 (8) ◽

pp. 2179-2191

Author(s):

Zainab Mohamed ◽

Abd Ghani Rafek ◽

Mingwei Zhang ◽

Yanlong Chen ◽

Thian Lai Goh ◽

...

Keyword(s):

Risk Assessment ◽

Laser Scanning ◽

Rock Slope ◽

Regional Scale ◽

Development Program ◽

Information And Communications Technology ◽

Rock Fall ◽

The Hill ◽

Limestone Hill ◽

Landslide Disaster

The United Nations Development Program agenda 2030 has charted out seventeen Sustainable Development Goals (SDG) whereby Malaysia as a member has strategically set the platform for growth. From the seventeen agendas, the SDG 9 (built resilient, promote inclusive and sustainable industrialization and foster innovation) and SDG 11 (make cities and human settlements inclusive, resilient, and sustainable) requires a paradigm shift from conventional engineering approach for environmentally induced disasters. Leveraging multidisciplinary ability and information and communications technology (ICT) in the landslide disaster studies had enabled regional-scale information acquirement for hazards identification, exposure, and risk assessment to meet the goals. The investigated limestone hill, Batu Caves is located within the suburban city of Kuala Lumpur. The land use around the hill is extensive and the area is highly populated with encroachment to the toe of the limestone hill. The purpose of the risk study was to assess the limestone hill’s stability and hazards and the exposure that may lead to the vulnerability of the residences and commercial activities at and around the hill. Therefore, an engineering risk assessment study was carried out to determine rock fall hazard potential. The Terrestrial Laser Scanning survey was utilized to obtain the hillside’s cross section. Discontinuity mapping was conducted to identify rock block size and rock slope was analyzed using rock mass classification system to determine rock slope quality. The rockfall analysis was conducted to identify rock rollout distance and produce rock fall hazard maps. The Slope Mass Rating for the slope BC1A, Parcel 1, Batu Caves was determined as 61, and is classified as a partially stable. The maximum rollout distance at this slope was 11 m. This illustrates the practical output of this study that can be applied for mitigation and future development of the area.

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