Browsing by Author "Nawagamuwa, UP"

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item: Conference-Abstract
Compaction characteristics of municipal solid wastes at open dump sites in Sri Lanka
(2014) Nawagamuwa, UP
The majority of municipal solid waste (MSW) generated in Sri Lanka is disposed in open dump yards. Compaction of wastes at such open dumps is the main factor that controls short-term density and resulting placement efficiency of wastes in the dumps. Maximizing waste density allows reducing dump yard space requirements. Density | influences the stability of dump yards with high shear strengths. Combined moisture - density characteristics influences the hydraulics response and compressibility of wastes. Further, lot of civil engineering constructions in Colombo city area has been commenced on the lands previously used for dumping of waste. Construction on already covered dump wastes will give lot of problems such as high settlements, slope instability, shear failure etc. Four dump yard locations such as Bloemandhal, Seeduwa, Negombo and Madampitiya were selected for the study and the moisture-density relationship was studied. Some of these locations are now abandoned and the land being used for construction activities and some are still in the process of dumping. It was observed that the compaction behavior of waste was similar to that of soils with waste, but the shape of the compaction curve has deviated from the standard bell shaped curve established for soils.
item: Article-Abstract
The Curious case of the Khettarama pitch
Nawagamuwa, UP; Senanayake, AIMJ; Silva, SA
During the Compaq Cup tournament in Sri Lanka in September 2009, the teams batting under lights at the R. Premadasa (Khettarama) Stadium pitch consistently found it very difficult to bat and thus lost matches. Many were of the view that the pitch was helping bowlers a lot more during the evening making it very unfair for the team batting second. This paper is based on the study which was carriedout by the authors at the request of Sri Lanka Cricket (SLC)to investigate the behaviour of the.R. Premadasa Stadium (Khettarama) pitch. The study aimed to find out if there was any truth to the above claim by conducting insitu bounce tests and collecting top-dressing samples from the pitch at. regular time intervals. The test was conducted during the hours of a normal day /night One Day International match would be played at this stadium and match conditions were simulated as far as possible. The variation of bounce with time was then compared with the moisture variation through the course of duration of play to see whether there were correlations between the two. Further, a theoretical discussion based on unsaturated soil mechanics and soil science on the effect of these factors is also included for better understanding.
item: Conference-Abstract
Development of an alternative approach for bored and cast in-situ pile design using PDA test results
(Department of Civil Engineering, University of Moratuwa, 2021-11) Kaushalya, AAS; Nawagamuwa, UP; Hettiarachchi, P
Many pile designs are done as bored cast-in-situ end bearing pile designs in Sri Lanka and the reason for that is the availability of hard bedrock at relatively a shallow depth compared to other countries. These designs are mostly done using ICTAD/CIDA guidelines. However, many researchers have identified some issues that are generated with conventional pile design methods and construction procedures of the piles. Test piles are widely being used to check the accuracy of assumptions that are generated with the designs. End bearing and skin resistance of the rock are only considered in most of the pile designs in Sri Lanka. Because of this phenomenon, skin resistance of soil layers that have a high SPT “N” value is not considered for the capacity estimation. In this study, the applicability of estimation of carrying capacity of the pile considering the soil layers which have higher SPT “N” value was verified. Therefore, a comparative study was conducted together with two main research objectives. It was required to evaluate which design procedure is more effective when comparing the estimation of the pile capacity considering all the layers which have SPT “N” values more than or equal to 15 (as criteria 1) or the pile capacity only considering the skin and toe resistance in the bedrock (as criteria 2), and a comparison of the estimated allowable carrying capacity values according to the ICTAD/CIDA and Euro code 7 guidelines with the actual allowable carrying capacity values which were taken from the CAPWAP analysis of PDA test results was also considered as a primary objective in this study. As per the methodology, required data and information were gathered and the soil parameters were calculated by obtaining corrected SPT “N” values. Thereafter, allowable carrying capacity according to ICTAD/CIDA guidelines and design carrying capacity according to Euro code 7 guidelines were estimated for both criteria. The difference between the estimated values of both criteria was represented as a percentage. After selecting more suitable and applicable criteria, the capacity values which were estimated using those criteria were compared with actual allowable carrying capacity values. According to the analysis, the difference between the estimated values of both criteria were approximately ranged between 6% - 65% for the estimation according to ICTAD/CIDA guidelines and 16% - 150% for the estimation according to Euro code 7 guidelines. Therefore, the estimation of the pile carrying capacity considering all the layers which have SPT “N” values more than or equal to 15 is better predicted than the estimation of carrying capacity of the pile only considering the skin resistance of rock and end bearing of the pile. As per the comparison of the actual and estimated allowable capacities, it is possible to obtain overestimations or underestimations that will rely on the assumptions made about the properties of soil and rock layers. Therefore, the accurate soil parameters and properties should be maintained in estimations and, the geotechnical investigation of the site should be more accurate.
item: Conference-Full-text
Development of an undisturbed method to measure density of improved municipal solid waste using heavy tamping
(Department of Civil Engineering, University of Moratuwa, 2016-12) Basnayake, ABMRS; Nawagamuwa, UP; Hettiarachchi, MTP
The core-cutter method can disturb a sensitive municipal solid waste (MSW) sample when measuring dry density of the soil. A mechanism has been developed to reduce this disturbance significantly, thus trying to obtain an accurate value for the dry density. The “resistance to the penetration” parameter of the soil was used as the theoretical background to develop graphical solution. An instrument was developed to measure penetration per blow value and it was calibrated with actual dry densities using Proctor compaction test. This mechanism was used to measure the compaction effect of heavy dynamic compaction, used in a predetermined grid pattern on a prepared MSW sample.
item: Thesis-Abstract
Development of empirical correlations between California bearing ratio (CBR) and soil index properties.
(2015-02-28) Jayamali, KVSD; Nawagamuwa, UP
The California Bearing Ratio is a penetration test for evaluation of the mechanical strength of road sub-grades and base-courses. This can be used as a mean of designing the road pavement required for a particular strength of sub-grade by comparing the strength of different sub-grade materials. However; civil engineers always encounter difficulties in obtaining representative CBR value for design of pavement. Over the years, many correlations had been proposed by various researchers in which the soil index properties were used to develop these correlations. A study was carried out to find correlations between CBR value with soil index properties those best suit the type of soils in Sri Lanka. Analyses were carried out based on the published correlations and soil data obtained from several Sri Lankan project sites. Based on the results, it is observed that the current published correlations are not in good agreement with Sri Lanka soils. In addition, no typical range could be found based on the soil index properties. Mechanical Strength of soil depends not only on the soil type but also on the observable physical characteristics which significantly influence on a soil’s behavior. Therefore, a method is proposed for correlating soaked CBR value and compaction parameters with such index properties, for Sri Lankan soils. This research covers the entire soil types according to Unified Soil Classification System which are generally used as sub-grades and base-courses. Among the several soil index properties, Atterberg Limits and grain size distribution data are used in this regard as these tests are much more economical and rapid than Compaction and CBR tests. The correlations are established in the form of an equation as a function of different soil properties by the method of regression analysis. Finally, results of the laboratory test are used to compare with the results of regression equation for the compiled data for the validation of the correlation. Key Words : California Bearing ratio, Compaction Parameters, Index Properties, Regression Analysis
item: Thesis-Full-text
Development of fast and bouncy cricket pitches in Sri Lanka
Perera, WSU; Nawagamuwa, UP
Development of Fast and Bouncy cricket pitches in Sri Lanka Most cricket batsmen in Indian subcontinent face a great difficulty in batting against fast bowlers on English and Australian fast and bouncy cricket pitches. The lack of having such practice pitches in home is the main reason for their lack of performances in fast pitches. It had been discovered that the pace and bounce of a cricket pitch is governed by clay content, clay mineralogy, sand content, organic matter content and grass content of the top layer of a cricket pitch. Six local soils and one soil from India were tested for their index properties as the preliminary step. The soils which were fiilfilling the requirement of the soil properties of fast and bouncy cricket pitch material were selected along with the currently used soil for Sri Lankan cricket pitch preparation and used for the laboratory model studies. Six cubic samples for the frictic and bounce comparison were prepared inside the laborati y from selected three soils varying the swface grass content. The co-efficient of friction (\i value) and the co-efficient of restitution (e value) were determined by the bounce test and friction test respectively. Soils which had low value and high "e" value were selected as suitable soils for the further proceedings of the research. MU and TY along with MT (Mixture of both MU and TY) were selected to carry on further studies in an actual cricket pitches in order to check their ability to generate pace and bounce. Besides selected area of the cricket pitch was daily photographed and surface crack density was analysed using MATLAB software. MU was selected as the most suitable soil from among all tests soils and recommended to be used for the development of local fast and bouncy cricket pitches in Sri Lanka.
item: Conference-Abstract
Disaster research as a making tool for safer building practices
Nawagamuwa, UP; Rifas, AM
Natural disasters pose a growing threat to the development strategies of developing countries like Sri Lanka by destroying infrastructure and productive capacity, interrupting economic activity, and creating irreversible changes in the natural resource base. As Vermeiren (1993) says, with increasing frequency, countries are facing situations in which scarce resources that were earmarked for development projects have to be diverted to relief and reconstruction following disasters, thus setting back economic growth. Disasters also directly impact on the foreign exchange earnings capacity of a country, at a time when extra resources are needed to finance imports of food, energy, and inputs for the agricultural and manufacturing sectors. If sustainable development is to be achieved, countries will have to take effective measures to reduce their vulnerability to natural disasters. As a consequence, property insurance, the traditional mechanism for reducing economic risk from catastrophic events, is no longer as available or affordable as in the past. This development is now forcing property owners and developers to seriously look at other mechanisms to minimize the consequences of natural disasters. Time has come to practice disaster loss reduction in a systematic way, as an integral part of ongoing development planning and investment. The research community has produced a vast body of knowledge on structural and non-structural mitigation measures designed to prevent or reduce the impact of natural disasters. The problem is that this information remains to a large extent within the domain of the research community and its scientific papers. The challenge consists in translating this information into a format that can be understood by the development community, and in disseminating it to property owners, developers, and government planners.The benefits of long-term hazard mitigation go beyond economics, as the reduction in vulnerability to disasters contributes to individual security, social stability and sustainable development. Nevertheless, economic arguments built on a sound benefit-cost analysis are essential when one has to defend the use of scarce resources for investment in mitigation. In this paper, authors wish to share some of the findings from a study conducted on tsunami reconstruction in the East Coast of Sri Lanka.
item: Thesis-Abstract
Effect of compaction and moisture content on gas transport and water retention in landfill cover soil : Maharagama landfill as a case study
Ranasinghe, RHK; Nawagamuwa, UP; Kawamato, K
In Sri Lanka, Engineered landfills are not being used and only very few controlled landfills are available. The usual procedure is to cover the waste with a good cover soil without providing gas venting facilities. This can be found at Maharagama dumpsite too. Hazardous gaseous and liquid landfill emissions are major problems of landfills. Since gas venting facilities are not provided, pressure inside the waste layer is very high compared to the atmosphere. Hence cover soil of the waste disposal site plays a major role in emission of landfill gases. Once the solid waste is covered with soil these gases are released to the atmosphere with high pressure, through this cover soil. Therefore studying the cover soil parameters are of paramount importance in evaluating and predicting its future gas emission. The Soil gas diffusion coefficient (Dp) and Air Permeability (ka) govern transport and emission of gases to the atmosphere such as of green house gases and volatile organic chemicals in the unsaturated zone. Further, considering gas diffusion coefficient in free air (Do) in this study, soil gas diffusivity (Dp/Do) and air permeability (ka) were measured in the soil which was used as the cover soil of Maharagama waste disposal site. The objectives of the research study were (a) to study about the gas transport parameters of landfill cover soil and (b) to understand effect of compaction and moisture content of the soil on the gas diffusivity (Dp/Do) and air permeability (ka). Measurements were done in 100cm3 repacked soil samples at different compaction levels with the existing moisture contents( normal compacted samples) and soil water matric potentials from pF= 1, 1.5,2,3,4.1 ( pF = -log,!" If'matric potential in em H20), air dried and oven dried conditions( pF controlled samples). In-situ air permeability was measured at the field in order to compare the laboratory and field measurements. At the same time the methane concentration in the research area was measured and a methane concentration contour map was produced. The air permeability changes from 0 to 100 flm2 while the soil air content varies from 0 to 0.35 m3 m", For the pF controlled samples kavaries from 0 to 100 flm2 and soil air content varies from 0.02 to 0:35 m3 m-3. In the case of normal compacted sojl sample leavaries from 0 to 80 Jlm2 while the soil air content varies from 0 to 0.28 m3 mo3. The soil gas diffusivity changes from 0 to 0.09 for the pF controlled samples and o to 0.07 for the normal compacted samples. The increase of dry density and reduction of water content increases the amount of soil air content and hence increased the soil gas transport parameters. At the fully dry condition and the with the maximum soil air content and the gas diffusion is around 9% of the gas diffusion coefficient in free air. With dry conditions the changes of soil structure properties also affects the soil gas transport, especially for the soil air permeability. According to the methane concentration contour map the methane concentration is very close to the atmospheric methane concentration all around the ground area except at few hot spots. Considering the results of this research, Maharagama waste disposal site final cover soil can be expressed as a very less gas exchangeable material. However, it is a very good capping material and the produced landfill gas from the waste layer is trying to migrate through the loosely compacted points around the ground area (high methane concentration was observed in few loosely compacted points). Methane concentration contour map further verifies the experimental results. At the same time, due to low gas exchange through the cover soil, the waste layer will be maintained in an anaerobic condition and hence the green house gas (methane) production is definitely enhanced. In the future, methane emission could be increased through the loose compacted points. These points can become (hotspots) and the formation of the cracks around the ground area would also be possible with time.A long term study is needed to observe the future gas emission at this location.
item: Conference-Full-text
Effect of salinity on consolidation of peat
(Department of Civil Engineering, University of Moratuwa, 2016-12) De Silva, KHSS; Nawagamuwa, UP; Hettiarachchi, MTP
Peat is a problematic geotechnical material, which could cause large settlements when subjected to loading because of the consolidation effect. Other than the well known factors which can have an impact on consolidation of peat, according to Zhang and O’Kelly (2013) addition of salt grains also improves the primary consolidation rate of peat specimens. In this research, the impact of salinity of water for the rate of consolidation was analyzed. The samples were mixed prior to and after addition of salt to achieve identical samples. Kaolin clay samples were used as a control specimen and those samples had no considerable effect on consolidation rate with the addition of salt grains. It was found that under similar conditions of one dimensional loading, consolidation rate of peat can be increased with the addition of salt. For quantitative analysis further experiments are required.
item: Conference-Full-text
Effects of climate change on landslide frequencies in landslide prone districts in Sri Lanka; Overview
(2013-11-12) Rathnaweera, TD; Palihawadana, MP; Rangana, HLL; Nawagamuwa, UP
Recently antecedent rainfalls and short term high intense rainfalls have become a general weather condition in Sri Lanka. Most of the recently occurred landslides could have some possible relationship with this unusual weather condition. Unpredictable variability of climate could probably be due to climate change where many environmental changes are happening around the world due to the climate change or global warming. This paper discusses the effect of climate change on landslide frequency in landslide prone districts in Sri Lanka. Several factors, such as rainfall and temperature variation in the last decade are analyzed to assess their significance. Analysis confirms that these changes have a possible effect on landslide frequency in Sri Lanka. Based on these results, possible trend patterns due to climate change during last decade are identified.
item: Conference-Full-text
Effects of global warming on landslide frequencies in Ratnapura District, Sri Lanka - 2011
(Department of Civil Engineering, University of Moratuwa, 2011-12) Rathnaweera, TD; Nawagamuwa, UP; Ratnayake, N
Unpredictable variability of rainfall patterns could probably be due to global climate changes with the increased frequency of extream whether events. Infact, rainfall is the most relevant factor for the triggering of both shallow and deep - seated landslides in Sri Lanka. Landslides related to heavy rainfall cause widespread property damage and occasional loss of lives. in recent years, number of rain-induced landslides have been increased in the Ratnapura district due to heavy rainfall. One of the most critical concerns in landslide study at the moment is the potential link between climate change and the frequancis of mass movement occurrences. In this research and overall study of the climate change on landslide frequencies in Ratnapura, distric is done by analysis the trend of the rainfall and temperature variation patterns.
item:
Evaluation of cover soil properties of solid waste dumpsites in Colombo District, Sri Lanka
Harshani, HMD; Nawagamuwa, UP; Senanayake, A;
Landfill cover soils have to serve multiple purposes such as operational safety, environmental protection, recultivation and integration of the sites into the landscape. Cover soil properties must therefore be defined with respect to the thickness, bulk density, air permeability and the available field capacity. The primary objective of this study is to examine the cover soil properties of three selected landfill sites (dumpsites) in Sri Lanka in order to propose suitable cover soil properties for similar applications in future dumpsites. Soil samples were obtained from three landfill sites in and around the city of Colombo. Laboratory tests to establish compaction characteristics, air permeability, particle size distribution and Atterberg limits were performed to assess the suitability as landfill cover soils. The study showed that landfill covers with well graded soils comply with the dry density and air permeability values, as per the guidelines. In the absence of proper gas venting facilities, it is essential to study the permeability properties of the cover soil. All three landfill sites tested need to be retrofitted with leachate and gas collecting systems that meet the standards stipulated in the guidelines.
item: Thesis-Abstract
Evaluation of resilient modulus of unbound material to implement mechanistic-empirical pavement design(MEPD) in Sri Lanka
(2024) Ariyarathne, BHT; Nawagamuwa, UP
Road pavement design in Sri Lanka traditionally relies on an Empirical design. This conventional approach, however, is characterized by certain limitations, particularly in its reliance on indirect material properties such as the California Bearing Ratio (CBR) value. The drawbacks of this method may result in the overestimation or underestimation of pavement design, prompting a shift towards the more reliable and accurate Mechanistic-Empirical Pavement Design (MEPD) process. Despite the advantages of MEPD, its implementation in Sri Lanka encounters challenges, including the absence of laboratory and in-situ testing equipment for modulus testing, the lack of a comprehensive soil database/soil map, and the unavailability of typical modulus values for local materials. This research endeavors to address these challenges by focusing on the development of a relationship for predicting Resilient Modulus (RM) based on other index properties of the soil. Additionally, the study aims to establish a modulus-based soil database and create a soil map for MEPD designs. To achieve these objectives, soil samples were collected from 28 locations across the country, and their basic properties were determined. Modulus tests were conducted using a Light weight Deflectometer (LWD). The validity of existing relationships for predicting RM was assessed, and subsequently, a new relationship was developed specifically for local subgrade materials. Furthermore, past soil data collected on a district basis were utilized alongside the newly developed correlation to create a comprehensive Soil Map based on RM values. In conclusion, this research successfully formulated an RM predicting model tailored to locally available unbound materials in Sri Lanka within the MEPD framework. The established soil database and soil map hold significant potential to enhance the design of road pavements in Sri Lanka, contributing to a more reliable and sustainable road infrastructure. Keywords: RM, MEPD, LWD, CBR, Unbound Material
item: Conference-Extended-Abstract
Faster and bouncier cricket pitches using locally available clays
(2009) Nawagamuwa, UP; Senanayake, AIMJ; Silva, SA; Sanjeewa, DMI
Reasons for the lack of 'pace & bounce' in Sri Lankan pitches has been a topic of debate for a long time. In order to address this problem from an engineering perspective, soil samples from Test venue in Colombo were gathered, analyzed and then compared to available data from other countries. Local pitches were found to have high silt content, low clay content and low plasticity due to a difference in clay mineralogy. Small scale model pitches were built and then tested to find the effect of adding commercially available clays on the pitch characteristics.
item: Article-Abstract
Gas exchangeable properties of "Maharagama" open dump cover soil
Ranasinghe, RHK; Nawagamuwa, UP; Wickramarachchi, PNK; Kawamoto, K
In Sri Lanka, normal practice is to dump waste in low lands and cover with a good compacted soil without providing gas venting facilities. This can be found at 'Mahargama' dumpsite too. Once municipal solid waste is placed in landfills, complex sequence of biologically, chemically and physically mediated events occur relating to hazardous gaseous and liquid landfill emissions. Hence, cover soil of landfills/ open dumps plays a major role in emission of landfill gases, because gases are released to atmosphere with high pressure, through cover soil. Therefore, studying gas transport parameters of cover soil are of paramount importance in evaluating its future gas emission. Soil gas diffusion coefficient (Dp)and Air Permeability (ka) govern transport and emission of gases through soil. In this study, these parameters were measured in repacked samples at different water matric potentials. Methane concentrations were measured in site and a methane concentration contour map was produced to identify the gas emission from landfill. According to the observed data, the Maharagama cover soil can be expressed as a less gas exchangeable material (but a good capping soil). In the future methane emission can be increased through the loose compacted points and this can become hotspots. Further, formation of cracks around the ground area will also be possible.
item: Article-Abstract
Gas transport parameters for compacted reddish - brown soil in Sri Lankan landfill final cover
Wickramarachchi, P; Ranasinghe, K; Hamamoto, S; Kawamoto, K; Nawagamuwa, UP; Moldrup, P; Komatsu, T
Gas exchange through (he compacted final cover soil at landfill sites plays a vital role for emission, fate, and transport of toxic landfill f,ases. This study involved measuring the soil-gas diffusivity tDp/Du, the ratio of gas diffusion coefficients in soil and free air) and air permeability (k,J for differently compacted soil samples (reddish-brown soil) from the final cover at the Maharagama landfill in Sri Lanka. The samples were prepared by either standard Proctor compaction or hand compaction to dry bulk densities of 1.60-1.94 g cm='. Existing and modified models for predicting Dp/ Do and k" were tested against the measured data. The simple, single-parameter Buckingham model predicted measured Dp/ Do values across compaction levels equally well or better than a dry bulk density (DBD) dependent model and a soilwater retention (SWR) dependent model. The measured ku values for differently compacted samples were highly affected by the compactionlevel and the sample moisture preparation method. Also, for air permeability, a single-parameter Buckingham-type k" model was most accurate in predicting k" in the differently compacted soil samples. Equivalent air-filled pore diameters
item: Conference-Full-text
Identification of local soils for development of cricket pitches
(Department of Civil Engineering, University of Moratuwa, 2015-10) Perera, WSU; Nawagamuwa, UP; Hettiarachchi, MTP
Most of the Cricket batsmen in Indian subcontinent face a great difficulty in batting against fast bowlers on English and Australian fast and bouncy wickets. The lack of having fast and bouncy pitches in Indian subcontinent has led to this problem. It had been discovered that the pace and bounce of a cricket pitch is governed by clay content, clay mineralogy and grass content of the cricket pitch. Local pitches were found to have high silt content, low clay content and low plasticity due to a difference in clay mineralogy. In this research “Grumusol” clay was discovered in Murunkan with a comparatively high clay content which is fulfilling most of the required clay properties of a fast and bouncy wicket. Typical Sri Lankan clay sample used to prepare wickets, Clay sample from Bangalore and the local “Grumusol” sample from Murunkan were tested for the clay properties. Results showed that “Grumusol” is most suitable for constructing a fast and bouncy wicket. Other than the clay as the basic material grass plays a vital role in binding the basic material together and maintaining the required moisture levels in the wicket preventing the wicket from fracturing during the game period. Here, Crouch grass was selected as the most suitable type of grass to achieve the desired output of the fast and bouncy wicket.
item: Conference-Abstract
Identification of native vegetation for slope stability in the Southern Province, Sri Lanka
Nawagamuwa, UP; Mujahid, AHM
Traditional civil engineering approach in stabilizing critical slopes requires lot of skills and, financial aid. It has been observed that the slopes having natural vegetation seem to be less vulnerable to slope failures, Vegetation is multi functional, relatively inexpensive, self-preparing, visually attiractive, and does not require heavy or elaborate equipment for its installation. Information on role of vegetation, rainfall influence and erosion are discussed for clear understanding and to mitigate the impact of slope failure on lives. Vegetation with common and scientific names and its root system are mentioned and soils or relevant slopes are classified in both common and engineering point of view.
item: Conference-Abstract
Identifying potential geo-hazards in Hingurakgoda area linked to damaged houses
(Department of Civil Engineering, University of Moratuwa, 2024) Thushyanthan, S; Nawagamuwa, UP; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, C
Expansive soils pose significant challenges for construction projects worldwide due to their dynamic response to changes in moisture levels. This study focuses on identifying and categorizing expansive soils in the Hingurakgoda region, using data from the National Building Research Organization (NBRO) alongside advanced analytical techniques. By examining key soil parameters such as Atterberg limits, clay content, moisture content, and swell pressure, the research aims to understand the underlying causes of structural issues affecting buildings in the area. Spatial analysis tools like ArcGIS and Google Earth Pro were utilized to develop effective methods for recognizing expansive soils and understanding their geological relationship with marble layer cavities. The presence of minerals like smectite, montmorillonite , and illite in expansive soils significantly influences their swelling and shrinking behaviors. The study thoroughly investigates the geotechnical aspects of the soil, revealing complex underground conditions such as alluvial deposits and karstic formations, which exacerbate the challenges posed by expansive soils. The research emphasizes the importance of accurately identifying and categorizing these soils to predict soil movement and potential structural damage effectively. By combining insights from extensive data analysis and geotechnical studies, the study offers valuable recommendations for minimizing risks associated with expansive soils, thereby enhancing the security and durability of structures in the Hingurakgoda region. In this study, six different methods were utilized to assess the swelling potential of expansive soils: Seed et al. (1960, 1962a), Ladd et al. (1961), Ranganatham and Satyanarayana (1965), Carter and Bentley (1991), Chen (1988), and Vander Merwe (1964). Among these methods, the Vander Merwe (1964) method demonstrated the highest level of similarity in predicting soil swelling potential The method’s consistent performance across various test results suggests that it is the most appropriate approach for classifying expansive soils in the Hingurakgoda area. The accuracy and reliability of the Vander Merwe (1964) method make it a valuable tool for evaluating soil expansiveness and managing associated risks, providing a strong foundation for construction and mitigation strategies in regions prone to soil swelling. To further build on these findings, future research should prioritize increasing the number of soil sampling locations in Hingurakgoda. Expanding the sampling distribution would lead to more comprehensive data, allowing for more accurate spatial mapping and improved predictions of swelling potential. This approach would enable a more precise identification of high-risk areas, contributing to better-targeted risk mitigation strategies. By adopting an enhanced sampling strategy, future studies can significantly improve the reliability of soil classification and provide more effective guidelines for construction practices in regions affected by expansive soils. In conclusion, the study's findings underscore the critical role of accurate soil classification methods, particularly the Vander Merwe (1964) method, in mitigating the risks associated with expansive soils and ensuring the long-term stability of structures in the Hingurakgoda region
item: Article-Abstract
Improvement of local soils in order to make "Fast & Bouncy" cricket pitches
Nawagamuwa, UP; Senanayake, AIMJ; Silva, SA; Senanayake, DMI
The playing character of pitches varies considerably from country to country and generally, pitches in the Indian subcontinent are regarded to be 'slow, low & dusty' in contrast to Australian or South African pitches which are 'fast & bouncy'. Sri Lankan players find it particularly hard to adapt to fast and bouncy pitches because they seldom find comparable playing conditions at home. This project tried to address this problem by investigating the possibility of improving the soils used in local cricket pitches in order to make them produce 'fast & bouncy' pitches. Data was gathered from local pitches by collecting and analyzing soil samples from Test venues in thevicinity of Colombo. This data was then compared to available data from other countries, especially Australia (due to similar climatic conditions). It was found that local pitches had high silt content, low clay content and low plasticity due to a difference in clay mineralogy when compared to Australian pitches. It was hypothesized that by reducing the silt content and improving the plasticity by the introduction of Bentonite (a clay type with very high plasticity) in to the soil would produce a faster and bouncier pitch of similar character to those in Australia. Small scale model pitches were built and then tested to find the effect the additional Bentonite on the pitch characteristics.