Browsing by Author "Amarakoon, GGNN"

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item: Thesis-Abstract
Investigation of two-dimensional interaction between piles due to pile driving action
(2015-06-26) Amarakoon, GGNN; Puswewala, UGA
Pre-Cast piles, which are mostly friction piles, are commonly used as deep foundations for bridges, multi storied buildings and as tower foundations. During the design stage, Engineers are not fully informed of the effect on adjacent pile due to pile driving and minimum safe distance between two piles for driving. The research is to investigate the effect on adjacent piles due to pile driving and to suggest suitable minimum spacing between piles. Pile driving displaces adjacent piles. It is simulated numerically using Finite Element Analysis software package PLAXIS. This project investigates numerically the influence of spacing on the displacement of afore driven piles due to driving a pile in the case of driven piles, by using the Finite Element Method. Horizontal displacement caused by the above activities in the pile is used as the prime indicator of disturbance. Pile material and soils are idealized as linearly elastic materials and different soils are represented by varying the Young’s modulus and Poisson’s ratio. The pile is assumed as infinitely long walls and the smear zone is modeled around the pile using material of lower stiffness considering the compression of soil around. Pile driving is modeled by progressive expansion of a cavity and a parametric study is carried out with different soils and with different spacing. Investigation is limited only to the variation of lateral displacements at the head of the adjacent pile caused by the actions mentioned above. Finally, suggestions are made to validate the model, when relevant field data can be accessed.
item: Conference-Full-text
Seasonal changes and coastal erosion in the South Western part of Sri Lanka
(2008-05) Subramaniam, DN; Amarakoon, GGNN; Gunathunga, SGAS; Pathinayaka, RC; Indeewara, VGD; Vijitha, AVP; Rathnayake, NP; Karunaratne, S
Sri Lanka is an Island, the economy of which relies very much on the developments of the coastal region, which supports tourism and fisheries. In addition, especially in the South-Western part of the country, the infrastructure lays in the proximity to the coast and the land is more precious and valuable. Further, the constructions around the coastal expanse, alter the sand dynamics of the coastal belt, increasing erosion and deposition at specific points. The erosion cannot be identified at a glance in one day, but when considering long-term sustainable developments, the loss of expanse due to erosion becomes vital. Hence, in this study we analysed the erosion pattern and gross land loss along South-Western part of Sri Lanka, considering duration of 6 months (Jun/07 till Jan/08). The variations of beach profile were determined from leveling perpendicular to the beach at 10 predetermined locations at one month interval. Grain size variations were also analysed from the samples collected from the mean sea level from each sampling locations. A strong correlation was observed at this location between the monsoon and erosion, while at Egodauyana, Panadura Moya, kani Lanka hotel and Payagala revealed rapid changes in erosion/deposition. Although the rainfall influences the beach variation, longshore currents, tides and coastal features (natural and artificial) are found to be dominating at these locations.