Static and dynamic behaviour of Kuala Lumpur limestone

It is a well known fact that the local bedrock which acts as the foundation for many surficial structures plays a major role in establishing the damage potential of incoming seismic waves due to earthquakes. Seismic activities are definitely a geologic hazard for those living in regarded prone areas, but the seismic waves are invaluable for studying the interior of the Earth. To understand the influence of seismicity to rock behaviour we must first explore stress and strain of the subject rock. Malaysia is experiencing small-scale tremors due the local and neighboring seismic activities. Limestone, being the major portion of the underlying bedrock in Kuala Lumpur, will experience dynamic behaviour due to these activities. To foresee the dynamic behaviour, the static behaviour of rocks is being considered. However, the static and dynamic behaviour of rock corresponds to the rock lithology, physical and mechanical properties of the rock. This paper reviews the properties of Kuala Lumpur limestone and foresees the probable dynamic behaviour of the rock

Kinematic analysis of blocks in tunnel on the basis of discontinuities.

This paper demonstrates the advantages of using stereographic projections in kinematic analysis of rock blocks in excavation surface. The stereographic method is completed by planes and poles as points and lines on the horizontal surface and the block kinematic behavioral analysis is investigated in a rock free face subsequently. A block is considered to be an instable one when the intersection lines fall into the critical zone, this area is defined through the relationship between the friction angle of the stone mass and the slope of the free face respectively. It is possible to determine the movement of the blocks on the basis of the discontinuity position before any collapse or sliding happens

Effect of palm oil fuel ash (POFA) content on volumetric shrinkage strain of granite residual soil

Laboratory experiment was carried out to determine the effect of palm oil fuel ash (POFA) content on volumetric shrinkage strain (VSS) through drying process on the material to be used as hydraulic barrier in landfills. Granite residual soil treated with up to 15% POFA was compacted using standard and modified proctor compactive effort; with moulding water content between -2% to +4% of the optimum moisture content obtained from the compaction curves. Soil samples were compacted, extruded and allowed to dry in the laboratory at room temperature for a period of thirty days. The results showed that VSS increased with higher moulding water content and also at higher initial degree of saturation for all compactive efforts. The influence of POFA treatment generally showed a decrease in the VSS with increase in POFA content due to the pozzolanic property of POFA. It was concluded that VSS depends most on the moulding water content, percentage of POFA, initial degree of saturation and compactive effort

Geotechnical assessment of palm oil fuel ash (POFA) mixed with granite residual soil for hydraulic barrier purposes

This paper assesses the geotechnical properties of granite residual soil treated with palm oil fuel ash (POFA), a waste from the palm oil factory for the purposes of hydraulic barrier in landfills. Granite residual soil treated with up to 40% palm oil fuel ash (by dry weight of the soil) was compacted using standard proctor compactive effort at the optimum moisture content. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS) and unconfined compressive strength (UCS) tests were carried out. Results showed that the index properties of samples met the minimum requirement for it to be used ass a liner. The maximum dry density and optimum moisture content decreased and increased respectively. The influence of POFA treatment on the geotechnical properties generally showed an improvement with up to 15% POFA which gave the acceptable results with regards to its usability as a hydraulic barrier material in landfill

Mobility and fractionation of REEs during deep weathering of geochemically contrasting granites in a tropical setting, Malaysia.

In this study we describe the mobility and fractionation of REEs in two deep (up to 30 m) tropical weathering profiles developed on two granites from the Kuala Lumpur pluton, Malaysia, sampled at Cheras and Rawang. On the basis of Na2O and K2O both are S-type granites, but Rawang has higher CaO, MgO and FeO than Cheras and lower SiO2. With respect to Al-saturation Rawang is I-type and Cheras is S-type. We compared the two profiles in terms of total REEs, magnitude and changes in Ce and Eu anomalies, REE mobility and LREE/HREE fractionation. Rawang profiles have higher REE contents, display lower mobility for most except the heaviest REEs and show higher LREE/HREE fractionation than those from Cheras. These differences can be linked to differences in primary mineralogy and degree of weathering, the latter controlling the type and volume of secondary minerals. Specifically, bowl-shaped parent-rock-normalised patterns in the Cheras saprolites appear to be a result of apatite dissolution. Moreover, moderate weathering evident in lower Mineralogical Indices of Alteration (MIA) at Cheras has conserved parent rock REE patterns and fractionation factors in the saprolites. By contrast, more intense weathering observed in Rawang profiles has produced abundant kaolinite group minerals that have preferentially retained LREE, which consequently display high LREE/HREE fractionation. This study provides important insights into the factors controlling REE mobility during tropical weathering, and its potential as an indicator of weathering intensity

Shear behavior of crushed mudstone and claystone under macrostructural and microstructural approaches

This article discussed the shear behavior of crushed mudstone and claystone in Malaysia when subjected to short- and long-term immersion while staged compression-immersion-direct shear tests were performed. The crushed mudrocks were subjected to 5 stages of loading (50 kPa, 100 kPa, 150 kPa, 300 kPa, and 600 kPa) with and without immersion, whereby immersions were done at 100 kPa and 600 kPa vertical loads were referred to as long- and short-term immersion tests, respectively. A variable pressure scanning electron microscope (VPSEM) and X-ray diffraction (XRD) were employed for microstructural investigation so as to give a microstructural description of crushed mudrock failure upon shearing. It is found that short-term immersion had caused the crushed mudrocks to be less brittle while long-term immersion resulted in fully plastic straining behavior for both crushed mudrocks. XRD results revealed that claystone contained higher swelling minerals compared to mudstone, which explains the clod-form of claystone seen in VPSEM images. Based on both macrostructural and microstructural investigation, it is found that the crushed mudrocks are more susceptible to failure under short-term immersion, while long-term immersion caused the crushed mudrocks to achieve a stable state and be less sensitive to further moisture changes

Developing a comprehensive pavement management system in Tehran, Iran using microPAVER.

Decision makers often decide on maintenance and rehabilitation of pavements without any systematic procedure. These kinds of arbitrary decisions do not usually guarantee the effectiveness of budget allocation and cannot supply the maintenance needs of a network. A Pavement Management System is able to evaluate the existing condition of roads as well as predicting the future state. Therefore, choosing the most appropriate strategy of maintenance (the best choice with suitable time for execution) according to the available resources becomes possible. In this paper, MicroPAVER, which is one of the most comprehensive pavement management software was discussed. Implementation of different budget scenarios provided in this software such as: unlimited budget, annual budget, etc as well as practical methods of maintenance and other unique features help the decision makers to successfully manage the pavements on both network and project level by examining various trade-offs between allocated budgets. In order to indicate the efficiency of this system, some streets located in district No.6 of Tehran municipality (IRAN) were selected and MicroPAVER system was successfully used as pavement management system in this network. In this paper 10 main streets including 131 sections were investigated. The average weighted condition for each branch, during a design period of five years, was indicated to compare the effect of three different allocated budgets. In addition, ten deterioration prediction models were developed in this network

Effect of tire footprint area in pavement response studies

The necessity of incorporating realistic non-uniform measured contact stresses, tire footprint area, as well as other non-linear and viscoelastic behaviour within tire-pavement interaction have been suggested by many researchers in order to obtain more reliable pavement responses. However, modeling 3D contact stresses with distribution and other non-linear properties in common pavement design procedure seems difficult and impractical because of the complexity usually involved in this process. Therefore, layered linear elastic theory and average circular contact pressure have been widely used in most common pavement design procedures. In this paper, a simple but acceptable method for predicting pavement responses, in the existing layered linear elastic program (KENPAVE) was utilised. This modified method is based on incorporating tire imprint instead of load over inflation pressure ratio and utilizing a more realistic representative value rather than tire inflation pressure for uniform tire-pavement contact stresses. It was found that critical tensile stain at the bottom of HMA is underestimated, and accordingly fatigue life is greatly overestimated when using conventional method. In addition, based on the results of modified layered linear elastic method, new generation of wide-base tires (Michelin445/50R22.5, Michelin455/55R22.5) reduce vertical contact stress and pavement damage, since they provide wider area of contact and require lower inflation pressure. On the other hand, older generation of wide-base tire (Goodyear425/65R22.5) was considered more detrimental to the pavement in terms of bottom-up fatigue cracking

The use of analytical hierarchy process in priority rating of pavement maintenance

Decision makers often perform pavements repairs without considering the maintenance priority and without utilizing a systematic procedure. These kinds of arbitrary decisions do not usually guarantee the effectiveness of budget allocation.Rating approach in Analytical Hierarchy Process (AHP) is one of the most effective techniques in decision making process which was used to facilitate the prioritization of alternatives on the basis of important parameters like pavement condition index, traffic volume and road type. In this study, relative weights of criteria, sub-criteria and inconsistency rate in each pairwise comparison matrix were calculated with the help of MATLAB software, coded M-Files as well as Expert Choice software. Finally, with Ideal-Mode synthesizing in Expert Choice software, final weights for all criteria and sub-criteria were obtained. As a case study, a number of streets in district number 6 of Tehran municipality (Iran) were selected and the final rating model was run to determine the maintenance priority index for 131 sections. It was concluded that based on the existing conditions, the rating approach in AHP method prioritized the impaired sections for maintenance easily and effectively

The effect of soil cohesion and friction angles on reverse faults

Severe faults have caused many earthquakes around the world throughout history. More recently, earthquakes have occurred in Taiwan, China (Chi-Chi fault), and elsewhere, causing loss of lives and destroying many buildings and structures. These tectonic movements have gained attention from engineers, and in the past 15 years, the focus has been on faulting mechanisms. In this study, a physical model (1 g) was fabricated and used to evaluate the impact of a reverse fault in a field with a tunnel. In the 1 g model, researchers installed additional gauges on the tunnel, so that all the displacements could be adjusted, and all the responses could be monitored during faulting. An experimental study of various soil properties (cohesion and friction angles) in reverse faults on the tunnel lining were carried out and are described herein. A comparison of results for different levels of soil cohesion revealed that it can dramatically reduce the displacement by as much as 40%, and that friction angles of 27° can record approximately 60% more displacements than at 37°. Furthermore, a comparison of fault angles of 30° and 60° indicates that the displacements can be different by more than 43% in cohesionless soil and about 64% for a friction angle of 27°