ISERME - 2023

Permanent URI for this collectionhttp://192.248.9.226/handle/123/21322

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Now showing 1 - 20 of 27

item: Conference-Abstract
Analysing the Effect of Curing Temperature on Micro-annuli Formation in Existing Wellbore Cement Sheath for Underground Hydrogen Storage
(Department of Earth Resources Engineering, 2023-08-28) Thirukumaran, A; Perera, S
Cement is used in a wellbore to isolate the formation fluids from the adjacent geologic regions. However, the interfaces between cement and casing as well as cement and formation can develop into leakage conduits in the form of micro-annuli. The formation of micro-annuli is a result of poor bonding which can be related to differential stress asserted on the wellbore system due to the changes in temperature and pressure. Micro-annuli are a type of cement sheath failure that can lead to significant leakage depending on the type of fluid and geometry of the micro-annuli. Studies over the years have assumed and simplified the pore geometry to be homogenous and uniform. In contrast, recent studies have revealed the complex nature of the geometry of the micro-annuli. In this experimental work, effort was made to visualise the initial cement bonding in three-dimensional space. X-ray CT scanning was carried out on cylindrical composite samples prepared with sandstone and API class G ordinary Portland wellbore cement. The images were reconstructed and analysed using AVIZO. The effect of different curing temperatures is illustrated through the quantification of micro-annuli and by analysing their geometry.
item: Conference-Full-text
Analysis of efficiency and impact by deck charging patterns on rock blasting at Aruwakkalu Limestone Quarry, Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Surangani, RKH; Shanthilal, S; Sandaruwan, DLCD; Chaminda, SP; Samarakoon, KGAU; Senarathna, TMB
There is a potential to enhance both the efficiency and the quantity of explosives in limestone excavation utilising deck charge patterns in the Aruwakkalu limestone quarry in Sri Lanka. To achieve this a series of combinations with ANFO and deck charge patterns were simulated using a numerical analysis software named JKSimblast – 2D bench. This study entails simulating and validating the existing blasting geometry in the rock blasting practice. The fragmentation curves of the real world blast events were analysed and plotted using an AI platform called “Streyos”. Subsequently, the blasting geometry was optimised by adjusting the spacing and burden with different charge amounts. A comparison was made between the explosive energy distribution figures of the simulated blast with optimised blasting geometry and the deck charging blast series. To simulate the limestone condition for the rock mass, throughout different simulations, the rock specific gravity (SG) was defined as 2.6. Optimised spacing and burden for a 10.3 m deep and 72 mm diameter blast hole pattern were found as 2.9 m and 2.4 m respectively, ensuring favourable conditions with controlled ground vibration (5 mms-1) and air blast overpressure (120 dB). The optimal configuration for minimising boulder formation in the upper section of the hole was 23.17 kg of ANFO quantity per hole with a two-charge deck pattern.
item: Conference-Abstract
Analysis of topographic effects on tea yield in Sri Lankan tea estates using geomatics
(Department of Earth Resources Engineering, 2023-07-28) Randima, KAC; Malinga, DIGS; Kalpana, TMJ; Chaminda, SP
This research paper investigates the potential impact of hill shade on tea yield at the Dambatenne tea estate using unmanned aerial vehicles (UAVs). Drones were used to take high-resolution aerial photos of the location that was selected. The data were processed using Pix4D software to generate accurate 3D surface models, ortho mosaic maps, and vegetation indices. Additionally, the main goal of this study was to evaluate the impact of hill shade on tea yield. By analysing the obtained data, including vegetation indices derived from the multispectral imagery, the correlation between hill shade and tea yield was examined. Various mapping techniques and statistical analyses were employed to investigate this relationship. The findings suggested that there may be a relationship between hill shade and tea yield and that different levels of shading brought on by topographic characteristics may influence the development and production of tea. The findings from this research contribute to the understanding of how hill shade affects tea yield and provide insights for sustainable tea estate management practices. The results of this study are significant for tea estate owners and managers, as it highlights the importance of considering hill shade factors in optimizing tea cultivation and maximising yield.
item: Conference-Full-text
Applicability of GPR technique for earthen dam failures
(Department of Earth Resources Engineering, 2023-08-28) Arunapriya, GGDPI; Liyanage, AGSI; Kishanth, S; Premasiri, HMR; Ratnayake, NP; Abeysinghe, AMKB
A dam is a structure constructed across a river or stream to store water upstream from the obstruction. Dams are susceptible to damage for various reasons, which can lead to many catastrophic disasters. Therefore, identifying the dam's structural failures prior to a disaster is crucial. Drilling can be used for dam failure identification. But it is costly and destructive. Integrated geophysical methods have always helped in identifying subsurface features. In the current investigation, the applicability of ground penetrating radar (GPR) to detect potential failures in earthen dams was assessed. The Uyanwatta Lake earthen dam was selected as the study area during this investigation, considering the reported water leakage in this dam. A GPR survey was conducted with 100 MHz and 300 MHz antennas along five survey paths. Those are the top of the dam, 1.5 m below the top of the dam, and three distinct paths for the lake's spill. During the interpretation process, clay layers, fractured zones, gravel layers, and water seepage areas were identified. Those water leakage areas indicate that there has been a leak in the dam. Those results were compared with exploratory drill hole data from the Uyanwatta Lake Dam. Drill hole data has only presented information about the rock types present in the dam. But GPR data was able to provide information on loose sediments in the shallow depths of the dam as well. That indicates GPR data has the potential to provide additional information related to earthen dams.
item: Conference-Full-text
Assessing the potential of critical metals and rare earth elements in lateritic soils of the Southwestern region of Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Herath, HMIA; Piyumangi, WAM; Kanishta, KPMK; Abeysinghe, AMKB; Ratnayake, NP; Premasiri, HMR; Batapola, BDNM; Dilshara, RMP
Laterites are currently considered potential targets for critical metals (CMs) exploration considering their near-surface occurrence, large dissemination, and enrichment of CMs in lateritic soil during weathering. Although prominent lateritic formations are found in Sri Lankan geological terrain, the potential for CMs has not been explored yet. Therefore, the present study assesses the potential of CMs in laterites of the southwestern part of the country. 60 samples were collected covering the overall study area and processed for critical metal analysis. The metal concentrations of CMs: Al, Ni, V, Cr, As, Sr, Co, Sc, and REEs were determined from inductively coupled plasma-mass spectrometry (ICP-MS) and Li, Fe, and Al concentrations were determined from atomic absorption spectroscopy (AAS). According to the analysis, critical metals such as Cr, V, Ni, and Th were significantly high in laterite samples ranging from 42-419, 116-583.4, 274 – 1498, and 33 – 472 mg/kg, respectively. REE and other critical metals considered in the study including Co and Cu, showed comparatively low potential. The findings of the study emphasise that laterite soil has significant potential for Ni, V, and Cr, especially in low grades. The conclusion is this analysis will benefit future CMs' exploratory investigations by providing insights into the potential of CMs in Sri Lankan laterite deposits.
item: Conference-Abstract
Assessment of unusual rock weathering in Samanalawewa area in Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Rathnasekara, RMNL; Edirisuriya, EATD; Sajithkanth, T; Premasiri, HMR; Ratnayake, NP; Abeysinghe, AMKB
The research investigates the unusual rock weathering at Samanalawewa dam in Sri Lanka and its significant impact on the dam structure and surrounding area. While previous investigations covered physical, mechanical, chemical, and mineralogical properties, limited attention was given to physical observations. A comprehensive approach was conducted from physical observations, rock sample analysis, and scanning electron microscopy (SEM) to gain a deeper understanding of the weathering mechanisms and potential structural weaknesses. Samples were collected from the quarry site and surrounding locations based on geological maps from 13 locations in both fresh and weathered states. Various rock types were included, such as charnockite (CHA), garnet sillimanite biotite gneiss (GBN), marble (MAR), and khondalite (KHO). Physical observations focused on identifying distinct weathering patterns, colours, and textures on the rock surfaces. These changes happened only in the dam quarry site, not in the surrounding area in the Samanalawewa area. The SEM analysis provided valuable insights into elemental changes. Despite thorough examination, this research did not identify a significant correlation between the observed rapid weathering and the geological characteristics of the Samanalawewa dam and its vicinity. Further investigations are required to unveil the underlying factors responsible for this geological phenomenon and its potential implications for the dam’s stability and long-term viability.
item: Conference-Abstract
Comparative analysis of water hyacinth dynamics in North Bolgoda Lake, Sri Lanka: a classification based on high-resolution aerial imagery and satellite-imagery
(Department of Earth Resources Engineering, 2023-08-28) Dawalagala, HS; Radampola, A; Gowsigan, PT; Chaminda, SP; Dassanayake, SM; Jayawardena, CL
Water hyacinth (WH) is an invasive aquatic plant that has established its presence in tropical and subtropical regions around the globe. Its widespread existence has resulted in societal, economic, and ecological impacts that are mostly intolerable. Understanding and monitoring the spatial and seasonal dynamics of WH in the respective environments could provide insights to mitigate its environmental impact. This study attempts to identify seasonal patterns of WH within north Bolgoda Lake over four years (2019-2022). The methodology includes a pixel-based random forest (RF) classification utilising five distinct spectral indices in conjunction with raw Sentinel-2 spectral bands, operationalised through the Google Earth Engine (GEE) platform. The aerial imageries were classified using Esri ArcGIS Pro software. The outcomes of this study indicate an increase of WH proliferation during the wet season (May-November) over the dry season (December- April) with an overall accuracy of 82% for aerial imagery and 98% for satellite imagery. Data fusion techniques are proposed to overcome the limitations of employing two different forms of remote sensing data individually. Despite the challenges, this study reveals important insights into the scalability of input data to specific requirements and under restricted conditions.
item: Conference-Full-text
Critical evaluation of most suitable underground mining method for Kahatagaha underground graphite mine - a case study
(Department of Earth Resources Engineering, 2023-08-28) Ekanayake, EMKB; Bandara, TMW
Lanka has been a well-known natural vein graphite supplier to the world since 1820. This reputation is mainly due to its extremely high purity, the purity being above 99% carbon as in-situ status and no other country in the world has vein graphite deposits for commercial mining now. Vein graphite is mined at Kahatagaha, Bogala, Ragedara and also from a few smaller underground mines in Sri Lanka. For decades, the Kahatagaha graphite mine has been practising the ‘open stope mining method’ and this method itself does not require extensive mine support because high strength of host rock inside the mine. It can be thought that the behaviour of graphite veins especially inclined in nature and stable host rock could be the main factors to select above mentioned mining method. But, this mining method causes many practical issues now so that mine production, miners` safety and underground work supervision are badly affected. This research includes the study of the current mining method adopted at Kahatagaha graphite mine and its suitability compared with other mining methods used for narrow vein mining and proposing a mining method which is more suitable, safer, and more economical compared to the current practising method.
item: Conference-Full-text
Design and performance optimisation of graphite-based batteries for advanced energy storage system
(Department of Earth Resources Engineering, 2023-08-28) Liyanage, LDNM; Reval, SS; Madushan, IL; Rohitha, LPS
This research focuses on the development of a graphite-based battery, utilising the abundant graphite resources available in Sri Lanka while facing the challenges of limited access to advanced materials and technologies. The primary objective is to create a viable graphite battery that can potentially contribute to the advancement of energy storage technologies. Given the constraints in accessing certain materials and technologies, this study explores the electrochemical properties of graphite and investigates its potential application as a key component in battery design. Through systematic testing and optimisation processes, we aim to enhance the battery's performance and energy storage capacity. The outcomes of this research provide valuable insights into the potential of graphite-based batteries, serving as a stepping stone for future improvements and innovations in energy storage. Although the developed battery may require further enhancements, it contributes to the growing body of knowledge in sustainable energy solutions, benefiting both Sri Lanka and the global energy sector.
item: Conference-Full-text
Effect of feed size on fine grinding of dolomite from Naulla deposit, Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Gohulan, H; Jayaweera, BPDV; Deegayu, THSI; Mushmika, PAS; Samaradivakara, GVI
This study examines the crucial role that feed size plays in the fine grinding of dolomite obtained from Sri Lanka's Naulla deposit. The study is carried out at Metal Mix Pvt. Ltd. Galpatha site, a commercial facility that prepares dolomite for use in a variety of industries. By identifying the most efficient feed size range that improves comminution efficiency while attaining the desired particle size distribution, the main goal is to optimise the dolomite crushing unit, in particular the autogenous mill. The research process includes in-depth field tests and laboratory examinations. The effect of different feed size ranges on the grinding process is assessed by on-site studies. Analyses of the particle size distribution are performed based on the output of the autogenous mill to evaluate how well it performs with various feed sizes. The outcomes show that there is a distinct relationship between feed size and the effectiveness of fine grinding. According to the study, limiting feed size ranges from 1.5 to 4 inches which greatly raises crushability, cuts down on energy waste, and optimizes the grindability. The dolomite processing industry, where energy-efficient comminution is of utmost importance will be benefitted out of the findings of this study.
item: Conference-Abstract
Estimation of an extreme flood scenario induced by heavy precipitation, following wildfires for the North - Central California
(Department of Earth Resources Engineering, 2023-08-28) Dilshan, MWRR; Hiraga, Y; Kazama, S; Chaminda, SP
Wildfires and extreme precipitation scenarios are an increasing trend in the global context. Elevated risks of floods are expected to occur due to fire-induced land cover alterations. Hence, it is important to identify the impact of wildfire upon extreme runoff scenarios, under changing climate. This study focuses on the impact of the 2018 Ranch fire and the possibility of downstream flood risk in the Lake County of North - Central California. The soil and water assessment tool (SWAT) is used to estimate potential extreme flood scenarios brought on by high precipitation after wildfires downstream of Lake County. Using hydrological and meteorological data from 2000-2018, the SWAT model is set up and calibrated on a daily and monthly basis. Model calibration was performed after identifying 9 sensitive parameters, including the soil conservation service curve number (SCN-CN), and the model for pre-fire conditions agreed well with R2=0.83, NSE=0.81, and PBIAS=-17.8 values. The soil conservation service (SCS) curve number, wildfire burn severity, and land use are considered in determining the variation of discharge under the post-fire condition. Further research can be used to identify probable flood scenarios even in the context of post-fire low precipitation levels and to enhance simulation outcomes under various parameter modifications.
item: Conference-Full-text
Flood susceptibility mapping using explainable machine learning models
(Department of Earth Resources Engineering, 2023-08-28) Kurugama, KAKM; Kazama, S; Chaminda, SP
Flooding is one of the most frequently encountered natural disasters globally. Frequent severe flood occurrences in Rathnapura city, Sri Lanka caused damages to both human lives and infrastructures. Data-driven models have been showing their ability of flood susceptibility mapping (FSM) in data-scare regions as an alternative to traditional hydrological models, but they are not widely used by stakeholders due to their black-box nature. This research suggests utilising the shapley additive explanation (SHAP) method to interpret the results generated by the CatBoost machine learning model and to assess the influence of different variables on flood susceptibility mapping. A flood inventory (445 flooded locations) and thirteen flood conditioning factors were used to implement the model and results were validated using the area under curve (AUC) method, which showed a success rate and prediction rate of 93.1% and 92.5%, respectively. SHAP plots indicated that the regions with lower elevations and topographic roughness values, gentler slopes, closer proximity to rivers, and moderate rainfall are more susceptible to flooding. According to the results obtained, we suggest incorporating SHAP-based datadriven models in forthcoming studies on FSM to enhance the interpretations of model outcomes.
item: Conference-Full-text
Geomatics for monitoring rehabilitation Status in Aruwakkalu Limestone Quarry, Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Waravita, CS; Madhuranga, AU; Rodrigo, MAJ; Chaminda, SP; Jayawardena, CL; Samarakoon, KGAU
Aruwakkalu limestone quarry in Sri Lanka, owned and operated by Siam City Cement (Lanka) Limited, is one of the largest limestone deposits in Sri Lanka. Since the limestone deposit is seated in a shallow depth, it is being excavated by utilising opencast mining methods. The target main product from the extracted limestone is to produce cement. As the first step of ehabilitation, the land restoration is carried out by backfilling the mined-out areas with the previously stripped overburden material. To achieve the final landform, replantation of vegetation cover is formed by planting native trees on top of the re-filled land area. This study aims to evaluate UAV suitability for monitoring rehabilitation in the Aruwakkalu limestone quarry, geomatics-based vegetation analysis in rehabilitated areas, and the assessment of the drainage system of the study area. Aerial images were acquired from an UAV equipped with a multispectral sensor and the data was post processed by utilising Pix4D, ENVI, and ArcGIS software. The processed data was classified into different regions according to the rehabilitated year and further analyses revealed that there were certain areas which had poor vegetation cover which requires revegetation measures. Analyses of the terrain models of the study area revealed irregular drainage patterns, which need to be rectified by grading and forming better landforms. The findings provide valuable insights for monitoring and improving rehabilitation efforts in similar mining sites, contributing to sustainable mining operations.
item: Conference-Full-text
GIS-based analysis of coastal vulnerability in southern province of Sri Lanka: insights from Matara district coastal area
(Department of Earth Resources Engineering, 2023-08-28) Ratnayake, KM; Edirisooriya, KVUI; Rubasinghe, DM
Coastal erosion is a substantial natural hazard that is affecting both the environment and human communities globally. Sri Lanka's coastline is about 1600 kilometres, with rich biodiversity and resources, and faces growing coastal erosion, notably in the southern coastal region especially in the Matara District. Therefore, understanding the causes and effects of coastal erosion is essential. This study aims to evaluate shoreline changes from 2000 to 2020 (Weligama to Dikwella) and involves three stages such as mapping shoreline changes using satellite data (Landsat) a digital shoreline analysis system (DSAS), statistical analysis for shoreline changes rates over 20 years, identifying interplay between factors. DSAS measures shoreline changes using baseline approaches and results are presented for both northeast monsoon (NEM) and southwest monsoon (SWM) seasons. NEM shows coastal accretion in Matara due to sediment transportation, while SWM reveals erosion in Devinuwara through strong waves and sediment movement. Sea level rise, rainfall, and river flow correlations influence erosion patterns. Overall, this study emphasizes the use of advanced technology to understand and monitor coastal erosion, help decision-making and develop effective strategies for protecting coastlines.
item: Conference-Full-text
Heavy metal contamination in the water of a semi-urban lake – Bolgoda lake, Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) De Silva, NJC; Malinda, KMDRP; Elankeeran, T; Dilshara, RMP; Batapola, BDNM; Ratnayake, NP; Premasiri, HMR; Abeysinghe, AMKB
Urbanisation and industrialisation have intensified the heavy metal contamination in inland water bodies. Therefore, this study investigates the recent status of heavy metal pollution in the water of the Bolgoda Lake in Sri Lanka, a semi-urban inland water body that receives both treated and untreated municipal and industrial discharge from the surrounding area. A total of 11 lake water samples were analysed by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) to determine the concentrations of As, Cd, Cr, Co, Cu, Ni, Pb, and V. Their mean concentrations in the Bolgoda Lake water were 0.661 ± 0.264 ppm, 0.010 ± 0.004 ppm, 0.090± 0.018 ppm, 0.007± 0.002 ppm, 0.043± 0.039 ppm, 0.002± 0.001 ppm, 0.662± 0.264 ppm, and 0.091 ± 0.018 ppm, respectively. However, the derived contamination factors of the analysed heavy metals revealed that Bolgoda Lake is highly polluted with Cd (22.0) and V (13.2), whereas moderately polluted with Pb (1.8). Compared to previous studies, heavy metal contents in Bolgoda Lake water have increased significantly, especially Cd and Pb. Therefore, Cd, V, and Pb can pose the greatest threat to the ecological environment of Bolgoda Lake, thus effective strategies such as treatment or recycling of wastewater and industrial discharges are needed to protect this lake from further contamination.
item: Conference-Full-text
Heavy metals in agricultural soils and level of contamination with crop production
(Department of Earth Resources Engineering, 2023-08-28) Sumanathilake, RMSBD; Jegatheeswaran, N; Pabanda, KGM; Vijitha, AVP; Premasiri, HMR
Heavy metals (HM) can be defined as metallic elements that are greater than 40 in atomic weight and above 5 g/cm3 in specific gravity and cause abnormal effects on the biota at low concentrations. This study aimed to assess the levels of HM contamination in soils and unpolished rice grains (Oryza sativa) at three separated paddy cultivation fields in Anuradhapura, Gampaha, and Jaffna over one consecutive season. The concentrations of arsenic (As), cadmium (Cd), and lead (Pb) were detected using inductively coupled plasma mass spectrometry (ICP-MS). According to the results, HM concentrations of As and Pb in the soil for all studied fields were below the maximum permissible limits (MPL) set by the World Health Organization/Food and Agriculture Organization (WHO/FAO). However, Pb content in rice grains was high in all stations relative to the MPL for crops given by WHO/FAO. The results revealed that Cd has exceeded MPL of both soil and grains in the Jaffna paddy field according to the WHO/FAO guidelines and Cd has a high transfer factor (TF>0.27) from soil to grain among all concerned agricultural lands. Other heavy metals have lower TF values (0.001 to 0.131). Regarding the contamination factor, As, Cd and Pb showed a moderate level of contamination severity over three regions.
item: Conference-Full-text
Identification of optimum replacement ratio of processed quarry dust as a substitute for sand in cement plastering
(Department of Earth Resources Engineering, 2023-08-28) Madhurshan, R; Anuttara, RNS; Kannangara, KKEU; Illankoon, IMTN
The demand for sand is increasing due to construction activities. River sand scarcity causes illegal mining and environmental damage. The construction industry faces negative impacts if river sand becomes unavailable or scarce. Therefore, finding a suitable substitute is essential for the sustainability of the construction industry as well as preventing further degradation of the river ecosystem. Quarry dust, a byproduct of crushing is studied as a potential substitute. The investigation assessed the feasibility of using quarry dust as a partial replacement for river sand in wall plaster. Quarry dust was utilised to achieve the desired particle size distribution equivalent to that of sand. Five types of cement-sand-quarry dust wall plaster mortars were made. The volume ratios between sand and quarry dust were kept at 1:0, 4:1, 2:1, 3:2, and 0:1 while maintaining a constant cement amount for all mixtures. Then the strength and durability of plastering mortar were examined using destructive and non-destructive test methods. The obtained results were compared with wall plaster made from 100% sand. Results demonstrated that the optimal combination of strength, durability, and workability was achieved when using a sand-to-quarry dust ratio of 2:1. Also, this mixture reduced plastering mortar cost by 6%, recommending replacing 1/3 of the sand with resembled quarry dust for plastering mortar.
item: Conference-Abstract
Identification of the bedrock level with sub-bottom profiling data
(Department of Earth Resources Engineering, 2023-08-28) Rathnayaka, KRHI; Ansanayaka, AGNJ; Piragash, C; Wickrama, MDMG; Senarathne, EN; Ratnayake, NP
This study dominantly inquiries about the accuracy of the interpretation of sub-bottom profiling data for the identification of the bedrock level that is essential for underwater constructions and other marine activities. Although the physical core samples give the data more accurately, it is expensive and time-consuming. It stimulates the inspection of alternative methods such as sub-bottom profiling. A boomer profiler has been used in this study for the data collection from the north and west sides of the Colombo harbour in Sri Lanka with a 1 kHz frequency. The acquired data were processed using the SonarWiz software and visual identification was employed for the layer identification. The borehole data were utilised for the validation of the results and standard penetration test (SPT) values were crucial while concluding due to most interpretations showing the bedrock level from SPT-50 level with its stiffness. Re-sedimentation is an error occurring during the borehole investigation. Apart from that, equipment failures can be occur during the seismic survey. According to the interpretation, the bedrock level reflection signature is often associated with the SPT-50 level. However, deviations occur due to factors like layer thickness and absolute bedrock presence. To improve the accuracy of interpretation, various frequencies and different types of bedrock can be considered.
item: Conference-Full-text
Image analysis approach to determine the porosity of rocks
(Department of Earth Resources Engineering, 2023-08-28) Varnasuthan, S; Fernando, WTM; Dahanayaka, DS; Dassanayake, ABN; Wickrama, MADMG; Illankoon, IMTN
Accurate characterisation of rock porosity is essential for assessing its strength and durability. This study explores both conventional and image analysis methods for determining rock porosity of two types of rocks, Bibai sandstone, a hard clastic rock and limestone, a soft rock. Conventional methods for determining rock porosity involve physical measurements and laboratory analysis, while image analysis methods utilize advanced imaging techniques such as CT scans or SEM to assess porosity based on visual information extracted from rock images. While various image analysis approaches exist to determine rock porosity, questions arise as to which approach is applicable and whether the results are comparable to current conventional methods. Hence, this study focuses on comparing the accuracy of alternative image analysis approaches. Representative rock chips from each core sample were examined using SEM, and 2D porosity was evaluated through image processing with ImageJ software. The Avizo visualisation software was employed to assess Bibai sandstone samples' porosity from CT images. The research offers insights into the pros and cons of each approach, contributing to the enhancement of accuracy and efficiency in rock porosity evaluation, particularly in geology, mining, and civil engineering applications
item: Conference-Abstract
Integration of machine learning with numerical modelling for landslide susceptibility assessment near Uma Oya catchment, Sri Lanka
(Department of Earth Resources Engineering, 2023-08-28) Abeygunasekara, HA; Kazama, S; Chaminda, SP
Landslides being an abundant source of risk prevailing worldwide, the mountainous regions in the central part of Sri Lanka, experience numerous slope failures throughout the year. Many such slope failures have been reported following extreme rainfall events. Comprehension of the causative factors underlying these hazardous events hold much significance in developing control strategies for future disaster mitigation efforts. Numerical modelling and machine learning are distinct approaches that are widely being used in simulating hydrogeological processes and other environmental phenomena leading to disasters, the objective of this study was to investigate the use of an integrative approach of these two disciplines in evaluating the risk of landslide susceptibility with specific application to a site near Uma Oya catchment, Sri Lanka. The model incorporates a finite difference scheme for groundwater modelling coupled with slope stability evaluations using raster-based grid operations in GIS, analysed for two historical landslide cases within the region. The gradient-descent optimisation algorithm was adopted in optimising the groundwater model in which the results were in good agreement with the true observations, where the predicted water table levels exhibited a 78% recovery rate of true positives, justifying the usability of the adopted research framework in future disaster reduction endeavours.

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