Gua Lubang Kelawar Batu Tambah, Hulu Kelantan: tinggalan petempatan manusia

Gua Lubang Kelawar Batu Tambah merupakan sebuah tapak prasejarah yang terletak berhampiran dengan perkampungan orang asli di kawasan Hulu Kelantan. Tapak ini dikenalpasti sebagai sebuah tapak yang berpotensi sewaktu tinjauan awal yang dilakukan oleh Prof. Madya Dr. Zuliskandar Ramli dan pelajar sarjana dari Institut Alam dan Tamadun Melayu (ATMA) Universiti Kebangsaan Malaysia (UKM) pada bulan Disember 2016. Kajian ini dilakukan bertujuan untuk meneliti persekitaran dengan jumpaan artifak di gua tersebut. Kaedah yang digunakan dalam kajian ini lebih berfokus kepada kaedah ekskavasi arkeologi yang berasaskan kepada sistem grid. Fokus kajian ini ialah berkaitan dengan jumpaan artifak, ekofak serta lukisan gua yang menjadi bukti kepada penempatan masyarakat prasejarah dan masyarakat orang asli di Gua Lubang Kelawar Batu Tambah. Artifak yang ditemui ialah alat batu seperti kapak, batu pelandas, pengikis, alat penetak, pahat, batu pemukul dan puingan serta jumpaan pecahan tembikar tanah yang tidak bermotif serta yang bermotif cord mark. Penemuan ekofak yang dipercayai sebagai sisa makanan pula ialah seperti cangkerang siput dan tulang haiwan serta penemuan lukisan gua yang bermotif antropomorfik, zoomorfik, flora dan abstrak. Dengan adanya jumpaan artifak, ekofak dan lukisan gua telah menjadi bukti bahawa Gua Lubang Kelawar Batu Tambah pernah digunakan oleh masyarakat prasejarah serta turut digunakan oleh masyarakat orang asli

Pencirian sifat kimia bahan tanah pada cerun gagal di sepanjang jalan Ranau-Tambunan, Sabah, Malaysia

Kawasan kajian yang terletak di kawasan pergunungan pantai barat Sabah sering dikaitkan dengan kejadian tanah runtuh dan kegagalan cerun. Secara geologi, kawasan di sepanjang jalan raya Ranau-Tambunan (RTM) terdiri daripada cerun potongan batuan sedimen arenit daripada Formasi Crocker dan metasedimen argilit daripada Formasi Trusmadi yang telah terluluhawa serta beberapa bahagian yang terdiri daripada endapan Aluvium Kuartener. Pencirian sifat kimia ke atas bahan cerun tanah yang gagal di kawasan tropika, terutama sekali di kawasan kajian jarang dilakukan. Pencirian ini adalah penting kerana bukan ciri fizikal bahan cerun sahaja yang mempengaruhi kejadian tanah runtuh. Oleh itu, kajian ini memberi perhatian utama kepada pencirian sifat kimia dan mineralogi lempung telah dilakukan ke atas cerun-cerun yang gagal di kawasan kajian. Bagi mencapai objektif kajian ini, sebanyak 12 sampel tanah cerun gagal yang terdiri daripada luluhawa gred VI diuji. Analisis inventori cerun gagal menunjukkan terdapat 10 kegagalan cerun tanah (T) dan 8 kegagalan jenis khas (TB) dengan 3 kegagalan cerun dikelaskan berisi padu besar (> 500 m3), 7 cerun berisi padu sederhana (50 - 500 m3) dan 2 kegagalan cerun berisi padu kecil (10 – 50 m3). Analisis kimia menunjukkan kandungan organik tanah (BOT) yang rendah hingga sederhana daripada 3.75%-7.23%, pH tanah dikelaskan sebagai berasid amat tinggi hingga beralkali rendah. Analisis XRD menunjukkan komposisi mineral lempung utama terdiri daripada kaolinit dan ilit dan beberapa mineral lain seperti montmorilonit, haloisit, dickit dan vermikulit. Komposisi mineral bukan lempung utama terdiri daripada kuarza dan muskovit. Hasil kajian menunjukkan wujud perkaitan signifikan antara sifat kimia dan mineralogi tanah daripada segi pertukaran unsur kimia, hubungan air liang dan kekuatan ikatan butiran tanah dalam pembentukan mineral lempung yang menggalakkan berlakunya kegagalan cerun. Oleh itu, pembinaan dan pengurusan kerja-kerja potongan cerun bukan sahaja mengambil kira aspek sifat fizikal dan kejuruteraan tanah malah sifat kimia tanah juga amat penting terutamanya yang melibatkan batuan yang terluluhawa supaya sebarang kegagalan yang melibatkan cerun potongan dapat ditangani sewajarnya

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

Stability assessment of limestone cave: Batu Caves, Selangor, Malaysia

The limestone hill of Batu Caves is slowly being turned into a recreation park for slope climbing, base jumping and cave exploring. Quantitative assessment on the stability of the cave is essential to ensure the safety of tourists and visitors. The aim of this study was to quantitatively assess the stability of Gua Damai, Batu Caves, Selangor, Malaysia by using the Q system for rock mass classification, together with other factors such as cave width and thickness of the cave roof. The stability of the limestone cave wall was evaluated using Slope Mass Rating (SMR). A discontinuity survey conducted along the slopes beneath the opening of the cave showed that the rock mass comprised of four major joint sets labeled as J1, J2, J3, and J4 with the dip directions and angles of 110˚/73˚, 325˚/87˚, 243˚/39˚ and 054˚/30˚, respectively. The result of kinematic analysis showed that the dip direction/dip angle of a potential wedge failure was 051˚/59˚. By referring to the ratio of cave roof thickness with cave width, the results showed that the cave is stable. Based on the relationship between Q system and the cave width, the stabilities of Section 4 of Gua Damai is stable while Section 1, 2, 3, 5, 6, 7 and 8 require supports. Based on SMR, the cave walls stability at Portion c, d, and f were not stable while Portion a, b, e and g were stable. Overall, the most stable part of the cave is Section 4 followed by Sections 5 and 2. Sections 1, 3 and 8 are moderately stable while Sections 6 and 7 have poor stability

The intragranular textures of aggregates and its correlation to the physical properties

To evaluate the correlation of the intragranular textures on the physical properties of coarse aggregates, four aggregates samples consisting of three granitoid sources and one limestone have been studied. The role played by intragranular textures (mineral assembladge, grain size and grain boundaries) in influencing the physical properties are potentially significant to the fact that such textural variation may complicate the aggregate strength. This study indicates that the aggregates exhibited variation in textural habits. The granitoid aggregates, which is rich with silicate composition has typical heterogranular textures of porphyritic and equigranular grain structures. Whereas the limestone aggregate comprises of bioclast and peloid allochems cemented by micrite and spar. The granitoid aggregates showed better dispersed characters and had extremely interlocking crystal boundaries which have more physical strength compared to a carbonate aggregate

Mineralogy and geochemistry of rock aggregates and their relation to the interfacial transition zone (ITZ) in concrete

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Kebudayaan Hoabinhian dan Neolitik di Gua Jaya, Hulu Kelantan

Gua Jaya yang terletak di Gua Musang, Kelantan merupakan gua batu kapur yang dilihat berpotensi tinggi sebagai tapak hunian masyarakat prasejarah. Hal ini terbukti apabila penyelidikan awal dan percubaan ekskavasi telah dijalankan oleh Lamb dan Peacock pada tahun 1963. Hasil daripada percubaan ekskavasi tersebut, ia telah membawa kepada penemuan sebanyak 1500 serpihan tembikar sehingga Peacock merumuskan tapak tersebut sebagai lokasi pembuatan tembikar masyarakat kebudayaan Neolitik. Pada tahun 1993, Adi Haji Taha telah menjalankan tinjauan serta menemui beberapa serpihan tembikar di lantai gua tersebut. Berdasarkan tinjauan yang dijalankan, beliau juga melihat Gua Jaya sebagai sebuah tapak yang berpotensi tinggi sebagai tapak hunian masyarakat prasejarah. Pada tahun 2017 pula, pasukan penyelidik Institut Alam dan Tamadun Melayu (ATMA) telah menjalankan ekskavasi arkeologi secara saintifik dan sistematik di tapak tersebut. Oleh itu, kertas kerja ini akan memberi penumpuan kepada penemuan artifak dan ekofak ketika penyelidikan dan ekskavasi arkeologi fasa pertama dijalankan di Gua Jaya oleh pasukan ATMA. Antara jumpaan artifak di gua tersebut adalah merangkumi alat litik iaitu tungku, alat penetak, dan alat repeh serta pecahan tembikar. manakala jumpaan ekofak pula adalah seperti tulang binatang dan siput

Use of ultrasonic velocity travel time to estimate uniaxial compressive strength of granite and schist in Malaysia

The uniaxial compressive strength (UCS) is one of the most common mechanical parameters required in geotechnical engineering to characterize the compressive strength of rock material. Measurements of UCS are expensive, time consuming, destructive and thus, not favorable in the presence of limited samples. Therefore, a simple yet practical application is needed for the estimation of UCS. This research presents two correlations to predict UCS values for granite and schist by using ultrasonic velocity travel time (tp ) from ultrasonic tests. The validity of the practical approach presented in this research is confirmed based on the strong correlations developed from the experimental tests conducted. For the entire data set, the correlation between UCS and ultrasonic velocity travel time was expressed as UCS = 217.2 e-0.016(tp) for granite and UCS = 1110.6 e-0.037(tp) for schist and the coefficient of determination (R2 ) value for both granite and schist is 0.93. These correlations may be useful for applications related to geotechnical engineering designs