In the recent years, the impacts of floods have gained importance because of the increasing number of people who are affected by its adverse effects, especially in Beaufort area, Sabah, Malaysia. Flood destroyed critical infrastructures that are needed as shelter and also emergency relief for victim. This paper presents the findings of flood modelling undertaken to establish baseline and post mining flooding conditions during upstream storm and combination of upstream and downstream storm, respectively. A hydrologic model was established and calibrated based on 2014 flood. A structural approach by changing the physical dimension through dredging or sand mining between 2m to 3m is used for hydrology modelling is added into the existing floodgates and bunds. The outcome from sustainable sand is prevailing when it is able to reduce flood level for normal flow, upstream case, and both upstream and downstream case. Other findings are changes in velocity, shear and the significantly reduced power generated by the river during flooding.
Rock Mass Classification Systems (RMCS) can be of considerable use in the initial stage of a project when little or no detailed information is available. There is a large number of RMCS developed for general purposes but also for specific applications such as Rock Quality Designation (RQD), Rock Mass Rating (RMR), Rock Structure Rating (RSR), Geological Strength Index (GSI), Slope Mass Rating (SMR), etc. In this paper, we present the results of the applicability of the Rock Mass Rating (RMR) System for the Trusmadi Formation in Sabah, Malaysia. The RMR system is a RMCS incorporated with five (5) parameters: Strength of intact rock material, Rock Quality Designation (RQD), Spacing of joints, Condition of joints, and Groundwater conditions. A total of ten (10) locations were selected on the basis of exposures of the lithology and slope condition of the Trusmadi Formation. Trusmadi Formation is Paleocene to Eocene in aged. The Trusmadi Formation generally shows two major structural orientations NW-SE and NE-SW. Trusmadi Formation is characterized by the present of dark colour argillaceous rocks, siltstone and thin-bedded turbidite in well-stratified sequence. Some of the Trusmadi Formation rocks have been metamorphosed to low grade of the greenish-schist facies; the sediment has become slate, phyllite and metarenite. Cataclastic rocks are widespread and occur as black phyllonite enclosing arenitic and lutitic boudins with diameter up to a meter or demarcating thin to thicker fault zones or as flaser zones with hardly any finer grain matrix or as zones of closely spaced fractures. Quartz and calcite veins are quite widespread within the crack deformed on sandstone beds. The shale is dark grey when fresh but changes light grey to brownish when weathered. The RMR system for 10 outcrops ranges from 33.0 to 50.0 and its classified as “Fair” (Class III) to “Poor” (Class IV) rocks. The Fair Rock (Class III) recommended that the excavation should be top heading and bench 1.5 m – 3 m advance in the top heading. Support should be commencing after each blast and complete support 10 m from face. Rock bolts should be systematic with 4 m long spaced 1.5 m – 2 m in crown and walls with wire mesh in crown. Shotcrete should be 50 mm – 100 mm in crown and 30 mm in sides. While for the Poor Rock (Class IV), the excavation should be top heading and bench 1.0 m – 1.5 m advance in top heading. Support should be installed concurrently with excavation, 10 m from face. Rock bolt should be systematic with 4 m – 5 m long, spaced 1.5 m – 1.5 m in crown and walls with wire mesh. Shotcrete of 100 m – 150 mm in crown and 100 mm in sides. The steel sets should be light to medium ribs spaced 1.5 m only when required.
During the feasibility and preliminary design stages of a project, when very little detailed information on the rock mass and its geomechanic characteristics is not available, the use of a Rock Mass Classification Scheme (RMCS) can be of considerable benefit. Various parameters were used in order to identify the RMCS. The parameter comprised of Rock Quality Designation (RQD), Rock Mass Rating (RMR), Rock Structure Rating (RSR), Geological Strength Index (GSI), Slope Mass Rating (SMR), etc. In this paper, we present the results of the applicability of the Geological Strength Index (GSI) classification for the Trusmadi Formation in Sabah, Malaysia. The GSI classification system is based on the assumption that the rock mass contains a sufficient number of “randomly” oriented discontinuities such that it behaves as a homogeneous isotropic mass. In this study, the GSI relates the properties of the intact rock elements/blocks to those of the overall rock mass. It is based on an assessment of the lithology, structure and condition of discontinuity surfaces in the rock mass and is estimated from visual examination of the rock mass exposed in outcrops or surface excavations. A total of ten (10) locations were selected on the basis of exposures of the lithology and slope condition of the Trusmadi Formation. The Trusmadi Formation regionally experienced of two major structural orientations NW-SE and NE-SW. It consists mostly of dark grey shale with thin bedded sandstones, typical of a turbidite deposit. This unit has been subjected to low grade of metamorphism, producing slates, phyllites and meta-sediments and intense tectonic deformation producing disrupted or brecciated beds. Quartz vein are quite widespread within the joints on sandstone beds. The shale is dark grey when fresh but changes light grey to brownish when weathered. The results are classified as “Poor Rock” to “Fair Rock” in term of GSI. The poor categories (TR2 and TR7) represent slickensided, highly weathered surfaces with compact coatings or fillings or angular fragments. It is also characterized as blocky/ disturbed/seamy, which folded with angular blocks formed by many intersecting discontinuity sets. The fair categories can be divided into two (2) types; type 1 (TR1, TR6 and TR8) which represent as smooth, moderately weathered and have altered surfaces. It is also characterised as very blocky rock, which indicates interlocked, partially disturbed ass with multi-faceted angular blocks formed by 4 or more joint sets. Type 2 (TR3, TR4, TR5, TR9 and TR10) which represent as smooth, moderately weathered and have altered surfaces but characterized as blocky/disturbed/seamy, which folded with angular blocks formed by many intersecting discontinuity sets. It also has persistence of bedding planes or schistosity.
Foamed concrete has a tension weakness that can be mitigated by adding a suitable proportion of waste by-products such as mesocarp and trunk fibres. Accordingly, this study was conducted to explore the feasibility of using mesocarp fibre as a reinforcement in foamed concrete. Four varying percentages of mesocarp fibre were used: 0.2%, 0.4%, 0.6%, and 0.8% as an additive in foamed concrete. Two densities were cast and tested: 700 and 1400 kg/m3. After that, all foamed concrete specimens were prepared and tested on 7, 28, and 56 days. Mechanical properties were investigated in this study. The results showed that adding mesocarp fibre to lightweight foamed concrete enhanced its compressive, flexural, and tensile strengths. Because a coarser surface allows mesocarp fibre and matrix interlocking in the cured cement matrix, the surface roughness of the mesocarp has been shown to be favourable for fibre-to-matrix interfacial bonding. According to the findings of this investigation, for a density of 700 kg/m3, 0.4% volume fraction was the optimum quantity of foamed concrete applied to obtain the ideal mechanical properties while 0.6% of mesocarp was optimal for 1400 kg/m3.
This study intended to observe the effectiveness of foamed concrete jacketing using fibreglass fabric with the goal to enhance its durability properties. LFC of two densities of 500 kg/m3 and 1000 kg/m3 were cast and tested. The LFC specimens were wrapped with 1 layer, 2 layers and 3 layers of fibreglass fabric. The parameters evaluated were porosity, water absorption, drying shrinkage and ultrasonic pulse velocity. The results revealed that adding fibreglass fabric to LFC decreased its porosity and water absorption for both densities. Fibreglass fabric did more than only prevent cracks; it also reduced the drying shrinkage and increased the ultrasonic pulse velocity of LFC. Three layers of fibreglass fabric offered optimal results for all properties studied. As a result of the fibreglass fabric's ability to prevent moisture evaporation and consequent dimension changes in the confined LFC, drying shrinkage strain was kept least. The use of fibreglass fabric not only prevented water from escaping but also stopped it from penetrating the cement matrix. This preliminary study shows a huge potential to utilise fibreglass fabric as a strengthening medium to improve the durability performance of LFC.
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