Browsing by Author "Dassanayake, ABN"

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Adaptation to future flooding in a lowland city - a case of Jakarta city
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Kazama, S; Januriyadi, NF; Kure, K; Dissanayake, DMDOK; Dassanayake, ABN
Proceedings of ISERME 2020 ISERME 2020 104 Adaptation to Future Flooding in a Lowland City, - A Case of Jakarta City - *Kazama1 S, Januriyadi2 NF and Kure3 K 1Department of Civil and Environmental Engineering, Tohoku University, Japan 2Universitas Pertamina, Indonesia 3Toyama Prefectural University, Japan *Corresponding author – so.kazama.d3＠tohoku.ac.jp Abstract Hydrological model and inundation model are applied to Chilliun River Baisn including Jakarta City, capital of Indonesia to evaluate countermeasures as the adaptation in the future. For the future projection, rainfall data was made using 8 GCMs with statistic downscaling and bias correction. Future scenarios were prepared for land use change, land subsidence and 3 RCPs. Structural and non-structural countermeasures were evaluated as the adaptation for flooding. Only landuse change to 2050 increases 99% flood damage cost (almost double from current situation) and only land subsidence to 2050 increase 95% one. The combination of land use change and land subsidence makes 226% higher damage cost in 2050 than current one. This calculation shows the emphasis of both influences. Heavier downpour makes higher damage cost by flooding. Only future rainfall increases 77% and 99% on mean flood damage (annual expected damage costs) in around 2050 and 2100, respectively. However, the range of damage cost by each GCM is large and some models show the decrease of damage cost in 2050. The combination of land use, land subsidence and climate change shows 5 times damage cost to current situation.
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Analysis of beachrock samples along Southern and Western coasts of Sri Lanka by spectroscopic methods
(Department of Earth Resources Engineering, 2019-08) Edirisooriya, KVUI; Thilakarathna, MADP; Vijitha, T; Dassanayake, ABN; Jayawardena, CL; Dissanayake, DMDOK; Samaradivakara, GVI
Beachrocks are sedimentary structures commonly observed where there is warm sea water in tropical and subtropical regions as a result of cementation by CaCCb of coastal sediments in the tidal zone. Comprehensive studies have been carried out to determine the formation mechanisms of beachrocks specially Japan to improve an alternative countermeasure against erosion by man-made rocks. When focusing on formation mechanism of beachrocks elemental and mineralogical composition is vital. Considering this important application, we used spectroscopic techniques to understand composition of beachrocks in southern coastal region between Ahangama to Kaikawala and Uswetakeiyawa in the western coastal region of Sri Lanka. The presence of minerals in beach rock samples in southern coast were identified by FT-IR spectroscopic technique. The constituents of minerals present in the beach rocks are further confirmed by XRD technique. Elemental concentrations of beach rock samples have been analyzed using technique of WDXRF spectrometry. Uswetakeiyawa beachrock was mainly analyzed by using EDX in SEM. Beachrocks in southern coasts is comprise higher percentage of Aragonite which is the polymorph of CaCCb, frequently founded in most of the sites in the world. Further the composition shown similarities with Indian (Tiruchendru) and Japan (Okinawa) beachrock occurrences. Comparative to the composition of southern coast beachrock, XRD analysis did not indicate any CaC03 polymorphs Uswetakeyyawa, beachrocks. Instead it indicated the presence of Kutnohorite (Ca(Mn,Mg,Fe)(C03)2).
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Analyzing the seasonal variation of groundwater characteristics in the Attanagalu Oya basin
(Department of Earth Resources Engineering, 2019-08) Athukorala, DRM; Kohilan, C; Danushka, U; Jayarathna, WHDP; Chaminda, SP; Dassanayake, ABN; Hewavidana, SM; Dissanayake, DMDOK; Samaradivakara, GVI
Gampaha district which has the second largest population in the country consists of many industrial establishments and residential areas. Attanagalu Oya Basin which almost entirely the Gampaha district is a major hydrologic feature in determining the seasonal variations of groundwater characteristics in the region. In this study, the groundwater characteristics in the Attanagalu Oya Basin analyzed both quantitatively and qualitatively to identify variations in the pre and post monsoon periods. The qualitative parameters such as pH, conductance, turbidity, calcium, magnesium, nitrate, phosphorous, ferrous, and heavy metal concentrations were analyzed for samples taken throughout the entire basin for the two time periods: pre and post monsoons. The groundwater quantity variations were observed through data loggers and field surveys of water wells. These recorded values were used to model the groundwater resources in the region using two numerical models, MODFLOW by USGS and a self-written Fortran code. The qualitative and quantitative variations were then analyzed spatially and temporally to correlate with the upstream to downstream flow and the monsoonal recharge. The possible reasons for the observed trends and variations were also studied to provide recommendations for the sustainable management of the groundwater resources in the Attanagalu Oya Basin.
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analyzing the temporal variation of groundwater level in Attanagalu oya basin using numerical models
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Vinu, I; Udayanga, RMK; Chaminda, SP; Dassanayake, ABN; Dissanayake, DMDOK; Dassanayake, ABN
Scarcity for drinking water becomes one of the enormous threats around the world due to the increase in population, climatic fluctuation and pollution. Sri Lanka is considered as a country with little or no water scarcity when reckoning the whole country as one unit. However, several local regions have been identified with temporal water scarcity. Attanagalu Oya basin which covers almost the entire Gampaha district is a major hydrologic feature in determining the groundwater characteristics of the region. In this study, the temporal groundwater variation of the Attanagalu Oya basin was quantitatively analyzed. Using the data obtained from data loggers and field surveys, a numerical model for the groundwater in the basin was designed by using two software modelling approaches, a self-written Fortran code and Visual MODFLOW by USGS. Fortran code is mainly used for runoff modelling and Visual MODFLOW is for subsurface modelling. The quantitative variation obtained from the model was then examined temporally and spatially to correlate the upstream to downstream flow and monsoonal recharging impacts. The possible reasons for the observed deterioration and variations in the groundwater quantity can be contemplated as keys to providing recommendations for sustainable management of the groundwater resources in the basin.
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Applicability of ground penetration radar (GPR) technique to optimize soil Nail Wall designs
Lasan, HLI; Weerasekara, MN; Prashanth, S; Abeysinghe, AMKB; Premasiri, HMR; Samaradivakara, GVI; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Soil nailing is used to stabilize existing natural slopes or excavations using soil reinforcement technique. Due to lack of information on ground profiles and thickness of soil layers, the required soil nail lengths cannot be determined in advance, for most of the steep slopes. Furthermore, the cost of drilling in fresh rock is much higher than the cost of drilling in soft soil and weathered rock. Without proper information on the depth at which the fresh rock is found, a cost-effective soil nail wall design cannot be finalized. This research was focused on studying the methods that can be used for soil nail wall design optimization by applying Ground Penetration Radar (GPR). The study was carried out on an unstable slope near Nursing Training School located in Kandy in the central part of Sri Lanka.The physical properties of soil were determined by direct shear tests, and stability analysis was done by means of “Slope-W” software. GPR techniques were also used in this study. The investigation results showed that the existing slope is unstable, and necessary to be protected. Further, it was identified that the basement rock cannot be encountered at already designed depths of the soil nails, which was subcequently proven as correctbased on data from ongoing drilling for soil nail installations. With the precise knowledge about the underground geological structure using GPR technique, the drilling cost, nail transporting cost, nail off cutting time to complete the total work can be reduced.
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Applicability of pre-heating techniques for recovery of garnet from garnet biotite gneiss
Jayakodi, JDSU; Weliwita, BY; Nishanthan, SS; Samaradivakara, GVI; Abeysinghe, AMKB; Rohitha, LPS; Vijitha, AVP; ; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
In mineral processing industry, the highest energy is consumed by crushing and grinding operations. However, if we can initiate micro cracks in the hard rock pieces in advance, we should be able to reduce the crushing energy and liberate useful minerals economically. Various pre-heating techniques have been tried by the scientists around the world to liberate minerals from rocks. In this investigation, pre-heating techniques were used to liberate Garnet from Garnet Biotite Gneiss. The market price of Garnet varies with the particle size. Hence, the samples were crushed and sized into industry needed three size fractions: (+250-850) μm, (+180-250) μm and (-180) μm. Afterwards, by means of Wilfley Table, Garnet was separated from rocks. Final Garnet recovery percentage was recorded for different temperatures. Furthermore, energy calculation was done for each sample to get an idea about the power consumption. It was observed that the crushing strength decreases with the temperature increment and it has been proven by identifying propagation of micro cracks in thin sections, prepared from rock samples pre-heat treated in Muffle Furnace and Microwave Oven. The analysis reveals that the preheat treated and quenched samples give higher Garnet recovery than Garnet recovered from as-received samples of Garnet rich Biotite Gneiss.
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Application of emulsion explosive and comparative study on water-gel explosives for rock quarrying in Sri Lanka
Dharmaratne, PGR; Hemalal, PVA; Rohitha, LPS; Herath, B; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Dynamite has been the premier and the only high explosive used for mining and construction activities in Sri Lanka for a long period of time. Negative environmental impacts, effect on health and security hazards led to the Government of Sri Lanka (GOSL) to issue directives to find a suitable substitute for Dynamite. Subsequently, Water-Gel explosive was introduced in the year 2011. The poor performance of Water-Gels in wet conditions and it’s low Velocity of Detonation encouraged the use of Emulsion explosives. This research was focused on performing a comparative study of the performance of both Water-Gels and Emulsion explosives by analysis of the ground vibration and the blast air over pressures. The methodology adopted was to conduct ten blasts at one single metal quarry site keeping all other parameters constant. Blasting tests were performed using Emulsion explosives and Water-Gel explosives and the resulting ground vibration and Air-Blast overpressures were measured with Blastmate 111model for each blast. Calculation of mean fragmentation was done and particle size distribution based on photographic evidence of each blast was analyzed. Analysis was carried out demarcating the resultant production pile of aggregates covering a cleared zone. Grid lines inserted on the muck pile facilitated particle counting using photographs and calculating the mean fragmentation.
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Assessing the influence of microstructural features on deformation of rocks under triaxial loading
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Silva, SAV; Rathnapriya, RHDL; Riyasath, MSM; Dassanayake, ABN; Fujii., Y; Wickrama, MADMG; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Assessing the influence of microstructural features on the deformation of rocks under triaxial loading is vital in rock engineering applications, aiding safe and efficient operations by predicting the deformation of rocks. Triaxial testing offers the simulation of stress conditions within a rock to examine the deformation of rocks with confinements. This research focuses on how microstructural features, such as cementing material and pore geometry, affect the deformation behaviour of rocks subjected to triaxial loading. Two rock types were considered in this study: Kimachi sandstone (medium hard clastic rock) and Bibai sandstone (hard clastic rock). The progressive failure behaviour under Hydro Mechanical (HM) coupling effect was analysed by stress-strain distribution and the fracture geometry was examined using CT images of the specimens which were tested under different confinements. Thin sections were analysed to examine the changes in porosity and the effect on the cementing material with the confinement. The results of the proposed approach reveal a clear influence of the effective confinement on the failure of rocks and how it influences the porosity and cementing material of rocks. It is found that the Bibai sandstone shows a brittle failure and a shearing deformation while Kimachi sandstone shows a brittle to ductile failure and shearing to compaction deformation with the confinement due to the less presence of cementing material within Bibai sandstone compared to Kimachi sandstone. Therefore, with the confinement, the porosity of Bibai sandstone increases while it decreases in Kimachi sandstone. The results highlight the differences in the failure mechanism of a particular rock type for the same effective confinement which is a result of only a partial contribution of the pore pressure on the failure. These findings provide valuable insight into the assessment of microstructural features on the deformation of rocks under triaxial loading, aiding in the development of safer and more efficient rock engineering operations.
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Assessment of rare earth element potential in intrusive rocks special reference to massenna zircon granite
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Jayasuriya, JHAATS; Jayathilake, RGMA; Jeyakumar, J; Batapola, NM; Dushyantha, NP; Abeysinghe, AMKB; Premasiri, HMR; Dissanayake, DMDOK; Dassanayake, ABN
Sri Lanka has a geological setting that favors the presence of rare earth elements (REEs), which are currently identified as the most critical and strategic elements in the world. Previous geochemical studies show that intrusive rocks, such as carbonatites, pegmatites and granitoid rocks could be enriched of REEs. Therefore, this research is focused on assessing the REE potential in pegmatites with special reference to the zircon granite in Massenna. The collected samples from the focused areas were subjected for XRD analysis and monazite, apatite, allanite, bastnaesite, and loparite were found as the major RE minerals. Moreover, Massenna zircon granite has the highest REE potential, particularly LREEs and Y, compared to other pegmatites. The presence of REEs in the in-situ soil and sediment samples indicate that, REEs have been transported through weathering and erosion processes of the zircon granite, thus proving the REE potential in the source rock. Furthermore, REEs are mostly associated with felsic minerals rather than mafic minerals. Therefore, this research clearly provides insights of REE potential in the pegmatite bodies in Sri Lanka and more REE explorations need to be carried out in these prospects.
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Assessment of seasonal impacts on groundwater quantity and quality in upstream of Malwathu Oya Basin
Madhushankha, JML; Madhuwan, ARB; Menan, P; Chaminda, SP; Abeysinghe, AMKB; Jayawardena, CL; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Malwathu Oya Basin which covers 2350km2 located in Anuradhapura district is considerably populated and the safety and the available quantity of water is crucial for the people. Water samples were collected from selected locations during South- West monsoon period, Second Inter monsoon period and North-East monsoon period from September 2016 to March 2017. The samples were analysed for pH, turbidity, conductivity, fluoride, chloride, magnesium and calcium as basic drinking water quality parameters. Only the shallow regolith aquifers are considered for the study. The groundwater quality variation of the area shows a considerable variation from dry season to rainy season in general water quality of the area, and is in acceptable limit for most of the basic parameters. With the seasonal changes Fluoride and Chloride content is higher than permissible limits in some areas.
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Assessment of the effect of Aruwakkalu waste dump on surrounding water resources
(Department of Earth Resources Engineering, University of Moratuwa, 2021-12) Chirantha, D; Herath, HMDK; Chandrapala, HMNI; Chaminda, SP; Dassanayake, ABN; Jayawardena, CL; Dissanayake, DMDOK; Jayawardena, CL
In developing countries like Sri Lanka, waste management is a vital necessity. Solid waste dumps play a major role in handling waste in most countries. These solid waste dumps can cause severe environmental pollution via leachate generation and transport of toxic material along with both surface and underground water flows. The Aruwakkalu waste dump, which is the subject of the study, is a sanitary landfill situated in Puttalam district, Sri Lanka. The landfill is planned to receive and store municipal solid waste (MSW) from Colombo metropolitan area. Locations for these waste dumps must be selected strategically to minimise the risk of contamination of the surrounding environment. A distributed hydrological model was used to determine the effect of rainfall, evapotranspiration, and surface runoff on the site. It identified the direction of the water flow through the waste dump. The analyses have illustrated that the area receives lesser rainfall and a higher rate of evapotranspiration. The hydrological analysis illustrates the water flow direction from the waste dump to the outside is towards the West and away from the nearby settlement areas. The results were used to assess the effect of the waste dumpsite on the surrounding water resources.
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Bioremediation of lead-contaminated mine waste using microbially Induced carbonate precipitation
Mwandira, W; Nakashima, K; Kawasaki, S; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
The aim of this study was to use microbially induced calcium carbonate precipitation (MICP) technique to bioremediate lead using bacterium Pararhodobacter sp. Laboratory scale experiments conducted, achieved complete removal of lead. This result was further confirmed by SEM and XRD analysis that indicated coprecipitation of calcium carbonate (CaCO3) and cerussite (PbCO3). Furthermore, syringe test demonstrated that MICP based sequestration of heavy metals via coprecipitation with calcium carbonate may be useful for lead bioremediation. Very few low-cost in situ heavy metal treatment processes for lead bioremediation are available; therefore, bioimmobilization of lead by MICP has the potential for application as a low-cost and eco-friendly method for heavy metal remediation.
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Characteristics studies on engineering properties of river sand substitutes for conventional concrete and mortar works
Withanage, AK; Sugathadasa, AGMRP; Mithushan, T; Dissanayake, D; Rohitha, LPS; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
The main sand source of construction industry in Sri Lanka is river sand. However, being a developing country, the demand for river sand increases gradually. Based on engineering computations, sand demand for 2013 was estimated to be 12,266,186m3. The GSMB currently keeps records of all the licenses issued for sand mining and transportation, and according to these records the approximate annual sand supply is 7,132,631m3(GSMB records), which is far below the estimated demand. The difference may compensate by to illegal mining. Thus, this kind of unrestricted harvesting of sand is resulting in heavy rates of soil erosion; land degradation; increased river-water turbidity; lowered water tables; salinity intrusion in the lower reaches of rivers. Further, over use of river sand for construction industry has various undesirable social and ecological consequences. As a solution for this, various alternatives such as offshore sand, quarry dust, manufactured sand, dune sand, washed soil, waste building material, broken glass and blast furnace slag have been identified by various countries. Thus, this study attempts to identify suitable alternatives for river sand to mitigate the environmental issues related to river sand mining in Sri Lanka. In this project, we use manufacture sand, quarry dust, beach sand and off shore sand to test the suitability for conventional concrete and mortar works. Basically testing for concrete strength using uniaxial compressive strength and check grading of all river sand substitutes are performed. In addition to that two types of sand were mixed in various ratios and check those concrete and mortars for the compressive strength test to find the best mix ratio of sand for construction purposes. Finally those results were compared with strength of concrete for which river sand was used.
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Correlations between durability, mineralogy and strength properties of limestone
(Department of Earth Resources Engineering, University of Moratuwa, 2021-12) Senarathna, TMB; Janith, SHMPK; Dassanayake, ABN; Chaminda, SP; Jayawardena, CL; Dissanayake, DMDOK; Jayawardena, CL
Durability is used to depict the obstruction of rock to weathering and the pace of events of such changes. Wetting and drying cycles cause evaluation of physical changes and slaking behaviour of rocks, and that can be appraised by the slake durability test. Correlations between durability, mineralogy, and other physical-mechanical properties are different with the rock. Physical and mechanical characteristics of High-grade limestone samples and Lowgrade limestone samples from the Aruwakkalu mine were determined according to ASTM standard methods. X-ray diffractometer (XRD) analysis and scanning electron microscope (SEM) analysis were used to determine the mineralogical contents of the studied samples. Regression analyses were performed between the slake durability index and the physicalmechanical properties of limestones to identify the best wetting and drying cycle to assess the relationships. Differences between the physical, mechanical properties, and mineralogical contents of High-grade limestone and Low-grade limestone were also identified from the laboratory test results. Finally, this study will help to understand any rock engineering problem relating to durability, mineralogy, and other physical-mechanical properties of areas with limestone.
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Cost reduction of quality controlling in metal quarrying
(Department of Earth Resources Engineering, 2011-11) Basnayaka, LR; Samarathunga, SPGN; Susantha, TKJ; Nawaneethan, M; Wickrama, MADMG; Samaradiwakara, GVI; Dassanayake, ABN; Ratnayake, NP; Abeysinghe, AMKB
Quality controlling of aggregates is a major concern in aggregate industry. Cost of quality controlling can be minimized via finding correlations between different test on aggregates and rocks. Los Angeles abrasion value test, Aggregate impact value test, Uni-axial compressive strength test, Point load index and Schmidt hammer rebound value test were performed on a total of 22 gneissic metamorphic rock samples, which were collected from selected two quarries in Meepe and Nebada areas of Sri Lanka to investigate correlations between these test parameters. Correlations were developed between each parameter to reduce the cost of quality controlling by means of regression analysis. The study found a strong correlation between Loss Angeles abrasion value test and Aggregate impact value test. By analysing correlation between tests, mineralogy and rock properties validity of this correlation can be proved for common application
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Critical evaluation of current environmental comfort conditions of Bogala underground
Lasantha, MML; Thushath, T; Somarathne, KGMS; Hemalal, PVA; Dharmaratne, PGR; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Ventilation is a basic part of all underground mine operations as fresh, cool air is required to remove stale, affected air from the workings. The inadequate ventilation often is the cause of lower worker efficiency leading to decreased productivity and increased accident rates. This study focuses on the evaluation of environmental comfort conditions in Bogala Underground, a medium-depth underground graphite mine located in Aruggammana, Sri Lanka. A detailed ventilation survey was carried out taking measurements of dry bulb temperatures, wet bulb temperatures, Dry Kata and Wet Kata thermometer values, air velocities, surface air temperature and barometric pressures at strategic points covering the entire mine. All results were compared with corresponding standard values which describe the standard conditions to be met for working underground. Recommendations were made to improve the present environmental comfort conditions by installing auxiliary fans in stopes where necessary which will enhance the immediate mine environment contributing to health and safety aspects of the underground working environment.
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Demand estimating model to forecast the building material requirements for the construction and allied industries in Sri Lanka
Maduranga, WWDD; Nithushan, N; Jayasinghe, JKSN; Dissanayake, DMDOK; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Over the past few years, there has been a high level of interest in modelling demand estimation for the construction and allied industries in Sri Lanka. Demand estimation is a process that involves coming up with an estimate of the level of demand for a product or service and, typically confined to a particular period of time, a month, quarter or year. Demand estimation methods can be categorized into two main categories according to the technique applied to analyse data. Different approaches are survey methods and statistical methods. For a good quantitative analysis, statistical methods are more preferable. Regression analysis method which comes under econometric statistical method is more preferable to develop demand estimation models since it has high accuracy level. In the regression analysis, there are two methods to develop the model. These are Single Regression Analysis and Multiple Regression Analysis. The few steps to develop the estimation models are statement of a theory or hypothesis, model specification, data collection, estimation of parameters, checking goodness of it, hypothesis testing and forecasting. In this project, there are two models for sand and ABC materials each and the first model is for dust and ¾ particle size. Developed model for chip particles was rejected due to inaccuracy of the unavailability of required data. In validation, sand and ¾ particle size have shown very high accuracy when as dust and ABC has shown quite lower accuracy.
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Developing a casing design for the extraction of petroleum in Mannar basin, Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Harshapriya, IMP; Maduranga, GMS; Sandaruwan, SAL; Wickrama, MADMG; Dissanayake, DMDOK; Dassanayake, ABN
To develop an economical casing design program for the Mannar Basin which is safe, and risk minimized, knowledge on Pore Pressure Gradient, Fracture Pressure Gradient, Casing Performance Properties and Casing Design Criteria’s are important. Previous studies present the Hottman and Johnson (1965) method and D-exponent method-Eaton (1975) as accurate methods to predict the pore pressure gradient of the Mannar Basin and the Eaton (1969) method as the most accurate method to predict the Fracture Pressure Gradient of the Mannar Basin. The data extracted from the final well reports and pressure reports of the pearl 1 well of the Mannar Basin are analyzed using the above models to accurately predict the Pore and Fracture pressure gradients of the Mannar Basin. A specific casing design program is developed to suit the conditions of the Mannar Basin by selecting the casing setting depths and sizes and calculating the casing performance properties of Burst, Collapse and Tension, concerning the predicted pore pressure and fracture pressure gradients.
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Developing a hydrogeological model for Aruwakkalu limestone mine, Puttalam
(Department of Earth Resources Engineering, 2011-11) Dayarathna, EAC; Pethum, LLDI; Sunanda, DJ; Wedisinghe, WMCC; Dassanayake, ABN; Wickrama, MADMG; Ratnayake, NP; Abeysinghe, AMKB
A hydrogeological model has been developed for the Aruwakkalu limestone mine to study the behaviour of groundwater flow, associate with specific problems within the mine, in this research. Groundwater flow model was constructed using Visual MODFLOW 3D Finite difference method. Five distinct types of material layers were identified for material property designation in the study area of the mine by using the borehole data report, which was completed in year 2008. The mine is mainly bounded by two water bodies; Puttalam lagoon and Kala Oya. Existing hydrogeology related data and the results of several field tests were used to develop the groundwater model initially with a conceptual model. Utilizing hydrogeological data gained from field works; specially the aquifer parameters gained from pumping tests, the model was developed and calibrated for steady state conditions. According to the model simulation, groundwater flow is mainly towards the west direction and it simulates sea water intrusions in some locations. Dewatering feasibility and cost associated with groundwater movement of the mine can be evaluated using the developed model by conducting predictive simulations.
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Developing relationships among grindability, chemical composition and particle size of raw material mix at Aruwakkalu Limestone for Cement Production
Mendis, BSM; Jayathunga, THGS; Madurapperuma, HH; Rohitha, LPS; Dharmarathne, PGR; Hemalal, PVA; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y.
In this research study, the relationship among chemical constituents (SiO2, Al2O3, Fe2O3, CaO, MgO, Cl-, SO3, Na2O and K2O) and raw meal grindability are investigated on raw meal samples taken from the output of ball mill. The X - ray Fluorescence analysis is used to check the chemical composition and grindability is checked in the form of residue test of No 212 sieve residue. The distribution curves of the variables were analyzed to examine the skewness of the distribution. The Pearson’s Coefficient of Correlation analysis was performed on each two variables to identify any linear mathematical relationship between variables. The time series analysis was carried out to find the best fitting curve between grindability and the variables. Scatter plot analysis was finally performed and the results show the effect of chemical components and particle size distribution of raw meal were found to be range correlated on the raw meal grindability. The most suitable chemical constituent range to improve the grindability of raw meal are given based on 68% , 95% and 99% confidence intervals. The quality parameters such as Lime Saturation Factor, Alumina Ratio and Silica Ratio also evaluated based on chemical constituent values of 68%, 95% and 99% confidence intervals.