Pencirian geomekanik jasad batuan dan analisis kestabilan cerun di Laman Granview, Saujana Puchong, Selangor, Malaysia

Satu kajian pencirian geomekanik jasad batuan dan analisis kestabilan dua cerun terletak di tapak pembinaan Laman Granview di Saujana Puchong, Selangor telah dijalankan. Kawasan kajian merupakan sebahagian Formasi Bukit Kenny. Kajian telah dijalankan pada dua buah cerun potongan di tapak binaan adalah survei ketakselanjaran dan pencirian mekanik batuan. Kuarzit adalah litologi yang dominan di kawasan ini dengan sedikit filit. Ujian mekanik batuan berikut dijalankan: Ujian kekuatan mampatan sepaksi, ujian indeks beban titik dan ujian kekuatan regangan Brazil, ujian pantulan tukul Schmidt dan ujian Skleroskop Shore. Ujian kemiringan untuk penentuan kekasaran permukaan satah ketakselanjaran dijalankan pada sampel bongkah batuan. Hasil survei ketakselanjaran menunjukkan terdapat empat set ketakselanjaran yang utama di cerun L1 dengan nilai arah kemiringan/sudut kemiringan 62°/42°, 261°/79°, 281°/59° dan 237°/71°. Di cerun L2, terdapat tiga set ketakselanjaran utama iaitu dengan nilai arah kemiringan/sudut kemiringan 81°/41°, 171°/71° dan 198°/60°. Untuk ujian kemiringan, nilai purata sudut geseran puncak (fp) permukaan satah ketakselanjaran batu kuarzit dengan Pekali Kekasaran Kekar (PKK) 8-10 adalah 61°. Ketakselanjaran batuan kuarzit dengan nilai PKK 10-12 pula mempunyai purata sudut geseran puncak (fp) sebanyak 73°. Manakala, nilai purata sudut geseran puncak (fp) batuan filit dengan PKK 4-6 ialah 56°. Berdasarkan analisis kinematik, cerun L1 adalah stabil. Ragam kegagalan cerun L2 pula adalah kegagalan satah tetapi nilai sudut geseran permukaan satah yang tinggi akan menghalang kegagalan berlaku. Nilai perkadaran jasad batuan (RMR) bagi batuan kuarzit ialah 77 dan batuan filit ialah 66 dengan kedua-dua tergolong dalam batuan yang baik dalam kelas II

Kajian ketumpatan lineamen dalam penilaian potensi jatuhan batuan di kawasan Lembah Kinta

Perbukitan batu kapur di Lembah Kinta membentuk landskap muka bumi yang unik dan indah hasil daripada proses pelarutan batuan karbonat. Namun begitu, bergantung kepada kawasan perbukitan batu kapur tersebut, kehadiran pelbagai struktur geologi seperti struktur retakan dan kekar yang ekstensif mampu memberi ancaman kepada manusia dan harta benda. Kajian ini bertujuan melihat hubungan antara ketumpatan lineamen dan tahap kestabilan tujuh cerun gunung batu kapur di Lembah Kinta, Malaysia. Kajian ini terbahagi kepada dua peringkat, iaitu pemetaan ketumpatan lineamen dan penilaian kestabilan cerun dengan menggunakan kaedah Kekuatan Jasad Batuan (RMS). Sebanyak 599 lineamen rantau dikenal pasti dengan panjang keseluruhan lineamen mencapai 317 km. Seterusnya, peta ketumpatan lineamen yang dihasilkan dikelaskan kepada tiga kelas: Rendah (137.0-84.23) m, sederhana (84.22-46.83) m dan tinggi (46.82-0.0) m. Kaedah RMS yang dijalankan di lapangan pula adalah bertujuan bagi mengesahkan peta ketumpatan lineamen yang dihasilkan. Sebanyak dua belas stesen dinilai dengan tujuh parameter RMS iaitu kekuatan bahan batuan, tahap luluhawa, bukaan kekar, orientasi kekar, kelebaran kekar, ketakselanjaran dan aliran air bawah tanah. Setiap cerun yang dinilai dikelaskan kepada lima kumpulan daripada sangat lemah hingga sangat kuat. Skor RMS berdasarkan jumlah akhir setiap parameter yang dinilai. Hampir kesemua stesen yang dicerap berada pada kelas sederhana (Gunung Rapat, Datok, Kandu, Panjang, A, Tempurung) manakala hanya satu stesen (Gunung Lang) berada pada kelas lemah. Korelasi antara peta ketumpatan lineamen dan skor RMS menunjukkan korelasi yang baik dengan 73% ketepatan. Ini menunjukkan bahawa kestabilan cerun di Lembah Kinta dipengaruhi secara langsung oleh ketumpatan lineamen rantau

Assessment of ultimate bearing capacity based on the Hoek-Brown failure criterion

The ultimate bearing capacity is an essential requirement in design quantification for shallow foundations especially for structures built on large rock masses. In many engineering projects, structures built on foundation of heavily jointed rock masses may face issues such as instability and sudden catastrophic rock slope failure. Determination of the ultimate bearing capacity (Qult) of foundations resting on rock mass has traditionally been determined by employing several strength criterions. One of the accepted and widely implemented methods is to use the Hoek-Brown failure criterion 2002, where the required parameters are determined from a rock mass classification system, Geological Strength Index (GSI). This paper defines an assessment for ultimate bearing capacity (Qult) based on the Hoek-Brown failure criterion 2002 for a granitic rock slope beneath a 20 m diameter concrete water tank at Bandar Mahkota Cheras, Kajang, Selangor. Based on the Hoek-Brown failure criterion 2002, the ultimate bearing capacity (Qult) of rock mass was 7.91 MPa. The actual stress acting on the rock mass was 0.32 MPa. The assessment showed that the rock mass is safe since the ultimate bearing capacity (Qult) is 24.7 times higher than the actual stress acting on the rock mass

Peak friction angle estimation from joint roughness coefficient of discontinuities of limestone in Peninsular Malaysia

The peak friction angle (φpeak) roughness of discontinuity surfaces is a value that is fundamental to the understanding of shear strength of geological discontinuities, considering its importance in determining the mechanical properties of the discontinuity surface. It is however, both time and cost demanding to determine the peak friction angle as it requires an extensive series of laboratory tests. This paper presents an approach in the form of an experimentally determined polynomial equation to estimate peak friction angle of limestone discontinuity surfaces by measuring the Joint Roughness Coefficient (JRC) values in a field survey study, and applying the fore mentioned empirical correlation. A total of 1967 tilt tests and JRC measurements were conducted in the laboratory to determine the peak friction angles of rough limestone discontinuity surfaces. The experimental results were analyzed and correlated to establish a polynomial equation of φpeak = -0.0635JRC2 + 3.95JRC + 25.2 with coefficient of determination (R2) of 0.99. The laboratory results were also compared with theoretical results calculated from Barton’s linear equation. The results shown that estimation of peak friction angles were more accurate using the newly proposed polynomial equation since the percentage differences between measured and calculated peak friction angles is less than 6% compared to estimation from Barton’s linear equation where the percentage of differences is less than 11%. The proposed correlation offers a practical method for estimation of peak friction angles of discontinuity surfaces of limestone from measurement of JRC in the field

Evaluation of the content validity of the intrinsic-instrumental assessment tool for assessing the nature values of constructed wetlands

Constructed wetlands possess tremendous nature values, namely instrumental and intrinsic values. Constructed wetlands also store and capture carbon which help to mitigate climate change in sustaining our earth system. Hence, sound management of constructed wetlands must consider its importance as essential assets that increase their resilience in mitigation and adaptation strategies towards adverse effects of climate change. To examine the vital value of constructed wetlands, this study attempts to evaluate the content validity of the developed Intrinsic-Instrument Assessment (IIA) tool for assessing the nature values of constructed wetlands in the context of climate change. A methodological study was conducted to evaluate the content validity of the IIA tool in two-phases. First, a comprehensive literature review was conducted at the development phase to identify the construct and dimension, generate items and instrument formation. In the second phase (evaluation), a committee of six experts performed the content validity evaluation, and the content validity index was implemented for content validity quantification. Finally, the researcher conducted a discussion between the team members to finalise the items of the IIA tool. The first version of the IIA tool identified three domains (instrumental, objective and intrinsic values) with 36 items. The item content validity index (I-CVI) ranges from 0.833 to 1. The overall content validity index using the average approach, the scale content validity index (S-CVI/Ave) is 0.97. Thus, the IIA tool was evaluated with highly relevant and excellent content validity. Researchers generated 17 additional items in the IIA version 2.0 after considering experts’ feedback. Still, after the second evaluation by researchers, the final version of the IIA tool consists of 42 items. This paper contributes to the body of knowledge by performing the systematic process of the essential steps to verify the developed instrument’s reliability and validity, especially in the field of socio-ecology. This study provides comprehensive information and example as guidance for evaluating content validity for a new instrument scale. Also, it helps to bring insight into constructed wetlands’ vital nature values as the nature solution in mitigating and adapting climate change to advocate the sustainable development of constructed wetlands ecosystems

Wetlands estimation survey using DotS method: the case of Paya Indah Wetlands (PIW), Malaysia

Climate change poses a detrimental impact on the environment due to increasing carbon dioxide concentration in the atmosphere. In mitigating climate change, wetlands play a significant role in optimising the function of the earth's ecosystem for carbon sequestration and water resources rehabilitation. However, the effectiveness of wetlands management depends on an ecologically and statistically adequate dataset. Unfortunately, it is difficult for developing countries to implement area frame methods based on established sampling methods for data collection and monitoring. Thus, in this study, the dot sampling (DotS) method was adopted as it is simple, efficient, reliable and does not need a sample frame or high cost. DotS method uses the readily available platform, i.e., integration between Microsoft Excel-Macro (EM) and Google Earth (GE). This method systematically distributes the sample dots in GE's target area according to the locations generated by the EM. The field survey was then conducted at the sample dots of the target area in Paya Indah Wetlands (PIW) to ratify the site location. During the first stage, 72 dot sample locations were generated systematically, distributed across the target area, and 47 dot sample locations were located within the PIW. After the preparatory stage, 10 dot sample locations were eliminated. After the fieldwork inspection and evaluation, only 28 dot sample locations were selected as study stations. Hence, this study provides comprehensive data and examples applying the established DotS method with high reliability, accuracy, and rapidity in determining the number of study stations of wetlands. Based on the advantages, this study recommends the DotS method as a reliable survey method suitable for all study locations, especially in the ecology field. Applying the Dots methods as a surveying tool enables rapid land assessment in planning and suits the assessment of ex-mining constructed wetlands

Spatiotemporal dispersal study of mangrove Avicennia marina and Rhizophora apiculata propagules

The propagule dispersal pattern of the two common mangrove species, Avicennia marina (Forsk.) Vierh. and Rhizophora apiculata Blume at a mangrove fringed coast, in the southwest tip of Penang Island was examined. Propagule dispersal study of both species were carried out by release and recapture method, while early developments of propagule were observed by an on-site tethering system. A. marina propagules recorded higher dispersal rate as compared to R. apiculata. After 60 tidal cycles, almost all propagules had moved away from the initial release site under the influence of strong wave current. The A. marina propagules were observed to grow better and faster than the R. apiculata propagules. However, the propagules of both species eventually failed to establish at the study site due to strong wave effect as well as unfavourable soil condition. A. marina and R. apiculata were found to adopt different strategies in propagule dispersal and early growth. A. marina was notably better adapted to thrive in the coastal environment. In a similar open coastal area, wave current and soil condition are suggested to be the most critical factors affecting the mangrove propagule dispersal and early establishment

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

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

Lineaments And Their Association With Landslide Occurrences Along The Ranau- Tambunan Road, Sabah

ABSTRACT The purpose of this study is to assess the influence of lineaments on landslide occurrences based on the concept of lineament density. The Ranau-Tambunan districts with a 54 km road stretch from Ranau to Tambunan, crossing the Crocker and Trusmadi Formations is selected as the study area. In total, the study area is 844.7 km 2 . Both formations have similar area with Crocker at 405.5 km 2 and Trusmadi at 425.6 km 2 The rest are either igneous and alluvium (13.6 km 2 ). The lineaments were identified using a 5x5 weighted kernel filter on a -645 -Vol. 19 [2014], Bund. C 646 RADARSAT-1 standard mode image. The lineament density was calculated using a 1 km x 1 km grid on the lineament map and the density for each 1 km 2 grid is represented by the total length of lineaments in a grid. A total of 334 lineaments were identified with the lineament density map classified into three classes of density, resulting low (<318-m), moderate (319-775-m), and high (>775-m) using the natural break classification. The lineament density is more pronounced in the Crocker compared to the Trusmadi Formation. The influence of lineament on landslide occurrences was examined by overlapping the lineament density map with 75 landslides observed from fieldwork to determine the number of landslides in each density class. Out of the 75 landslides, 29 landslides occurred in the Crocker Formation and the other 46 landslides in the Trusmadi Formation. From the overlapped, a total of 47 landslides (63%) were captured into the high density class with 19 and 28 landslides in the Crocker and Trusmadi Formations respectively. These results indicate over half of the landslide occurrences are induced by the presence of lineaments with the highest percentage of landslides occurring in the Crocker Formation. As a conclusion, this study found that using the grid technique is an effective way to determine lineament density and quantify its influence on landslide occurrences

ROCK SLOPE STABILITY ASSESSMENT OF LIMESTONE HILLS, SOUTHERN KINTA VALLEY, IPOH, PERAK, MALAYSIA

The uniqueness of the karst topography of Kinta Valley is the result of the spectacular shaped steep-sided limestone towers. The instability of these hillslopes however, may affect the vulnerability of the surrounding area. This paper presents the results of slope stability assessment by using kinematic analysis to investigate the possible failure modes of 7 slopes in Gua Naga Mas (GNM1, GNM2 and GNM3), Gua Kandu (GK1, GK2 and GK3) and Gua Tempurung (GT) located in the southern part of the Kinta Valley, Ipoh, Perak. From the results of the slope stability assessment, it was determined that planar failure and wedge failure were the main failure modes. The GNM1 slope of Gua Naga Mas consist of four wedge failures and a planar failure with dip directions/dip angles of 005⁰/54⁰, 354⁰/59⁰, 124⁰/52⁰, 360⁰/50⁰ and 063⁰/70⁰ respectively. The GNM2 slope consists of a wedge failure with the dip direction/dip angle of 021⁰/64⁰. Two wedge failures and a planar failure were identified on slope GNM3 with the respective dip directions/dip angles of 336⁰/49⁰, 301⁰/68⁰ and 270⁰/71⁰. The GK1 slope for Gua Kandu consists of wedge and planar failures with dip directions/dip angles of 231⁰/49⁰ and 217⁰/49⁰ respectively. The mode of failure at GK2 slope was identified as wedge failure with the dip direction/dip angle of 154⁰/44⁰. No mode of failure was identified on slope of GK3. Slope GT of Gua Tempurung was identified to have two wedge failures with dip directions/dip angles of 011⁰/49⁰ and 321⁰/48⁰ respectively