• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.428-431
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• 2005

In this paper, the displacement and stress of pile foundation constructed in the soft cohesive soils were measured and investigated at each construction phase. The piles belongs to compressive stress then extension due to lateral flow of soft soils. Battered piles showed different stress state according to construction direction. The lateral displacements of piles radically occurred at the embankment phase.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.15-23
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• 2007

This paper presents a shoreline change analysis on a reclaimed land, using a pair of aerial photographs taken before and after the reclamation. Shorelines that are defined by a tide datum, i.e. Approximately Highest High Water Level, were mapped by both analytical and digital photogrammetric methods. The past shorelines were overlapped with digital cadastral map from which areas of retracted and protruded lands were computed. Magnitude of shoreline changes was estimated by calculating areas between the past and present shorelines. Comparisons in terms of areas showed a fairly good agreement between the two methods. However, particularly in the estuary of complex morphology, shoreline mapping by digital photogrammetric method requires images to be scanned at a resolution higher than 1200 dpi.

• Journal of the Society of Disaster Information
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• v.13 no.3
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• pp.305-312
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• 2017

In our society, the advanced, advanced, and information industries have continued to grow and now live in the era of the fourth industrial revolution. As the industry develops, the load of the users has also increased so much that it is deepened by the energy shortage phenomenon and the construction of additional energy facilities is required. Therefore, energy plant construction work is being actively carried out in the coastal area. In particular, it is common to build a plant in the ground by filling the coast with soil in other regions, reflecting the fact that Korea is lacking in the country when constructing power plants, gas and petrochemical plants. Current domestic grounding designs are designed or constructed to suit only the use of grounding resistors based on the electrical equipment design technical standards. However, in the case of a plant facility constructed in the untested buried soil, when the lightning current and the abnormal current are inputted, the facility operator or the user due to the elevation of the ground potential is seriously exposed to the risk of electric shock disaster. In this paper, we analyze the ground resistivity of the landfilled soil and use a computer program (CDEGS) based on KS C IEC 61936-1, We analyze the contact voltage and stratification voltage and propose a grounding design optimized for plant installation.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.39-47
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• 2016

In order to prevent leakage of leachate in offshore landfill, hydraulic barrier is indispensable. In the case of rubble mound revetment at offshore landfill, HDPE sheet in slope should be installed. In this study, seepage analysis were performed to evaluate seepage and flow in the seabed and revetment according to extended length of HDPE sheet by using SEEP/W. Results show that, in the case of low permeability layer is distributed where extended length of HDPE sheet was more than 1m, seepage flux in seabed and revetment was greatly reduced. In order to prevent seepage in seabed and revetment in the case of sand layer of high permeability is existed above low permeable layer, extended length of HDPE sheet and impermeable improvement width of permeable layer should be more than 1m at seabed.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.312-331
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• 2019

An offshore waste disposal facility refers to a landfill site for final landfilling of stabilized inorganic solid waste such as land and marine waste incineration materials, and the aim of such a facility is to solve the problem of insufficient waste disposal space on land and create and develop environmentally friendly marine spaces. The purpose of this study is to prepare guidelines for the construction of offshore waste disposal facilities, which reflect the need and importance of paying sufficient heed to environmental considerations from the initial stage of the project, in order to investigate, predict, and assess how such guidelines will affect the marine environment in relation to the construction of offshore waste disposal facilities, with the goal of minimizing the impact on and damage to the environment. For the purpose of this research, guidelines focusing on the construction of offshore waste disposal facilities were derived through an analysis of domestic cases and similar foreign cases and an assessment of their level of compliance with existing EIA guidelines through the operation of a discussion forum. In order to review the EIA report on similar cases in Korea, 17 EIA documents (2005~2016) for dredged soil dumping areas and ash ponds of thermal power plants were analyzed to investigate the status of marine organisms, marine physics, marine water quality, and marine sediment and to understand what types of problems can occur and what improvement measures can be taken. The purpose of these guidelines were to minimize damage to the marine environment by promoting EIA protocols in accordance with scientific and systematic procedures, to reduce the consultation period related to projects, to resolve social conflicts, and to reduce economic costs.

• Journal of the Korean GEO-environmental Society
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• v.17 no.8
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• pp.29-37
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• 2016

In order to prevent leakage of contaminants in offshore landfill, vertical barrier should be installed. Vertical barrier should be installed at designed depth of seabed to prevent the horizontal transport of contaminant in the subsurface. In this study, the seepage and contaminant transport in the subsurface according to embedded depth of vertical barrier were analyzed by using 2-D finite element analysis program SEEP/W and 3-D finite difference analysis program Visual Modflow. Numerical modelling results show that seepage flux and contaminant transport in seabed was greatly reduced when vertical barrier was installed at certain depth of low permeable layer. Therefore, the determination of minimum embedded depth for preventing contaminant leakage is helpful to design the economical vertical barrier.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.35-44
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• 2022

The V_S30 map is used as a key variable for site amplification in the ShakeMap, which predicts ground motion at any site. However, no V_S30 map considering Korean geology and geomorphology has been developed yet. To develop a proxy-based V_S30 map, we used 1,101 V_S profiles obtained from a geophysical survey and collected proxy layers of geological and topographical information for the Korean Peninsula. Then, V_S30 prediction models were developed using linear regression analysis for each geological age considering the distribution of V_S30. As a result, models depending on geomorphology were suggested per each geologic group, including Quaternary, Fill, Ocean, Mesozoic group and Precambrian. Resolution of map is doubled from that of V_S30 map by U.S. Geological Survey (USGS). Standard deviation of residual in natural log of proxy-based V_S30 map is 0.233, whereas standard deviation of slope-based USGS V_S30 map is 0.387. Therefore, the proxy-based V_S30 map developed in this study is expected to have less uncertainty and to contribute to predicting more accurately the ground motion amplitude.

• Korean Journal of Plant Resources
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• v.23 no.2
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• pp.187-196
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• 2010

A total of 10 islands (Kumodo and Komundo in Yeosu City; Oinarodo in Goheung County; Chongsando, Soando, and Pogildo in Wando County; Chodo in Jindo County; Uido, Huksando, and Hongdo in Shinan County) were surveyed to confirm distribution of naturalized plants from June 2006 to December 2008. A total of 100 naturalized plants taxa from 25 families were recorded. The highest number of naturalized plant species (82 taxa) was recorded on Oinarodo, while the lowest number was recorded on Hongdo (42 taxa) and on Uido (34 taxa). A total of 26 naturalized species taxa (such as Dactylis glomerata, Lolium perenne, Bromus unioloides, Rumex obtusifolius, Chenopodium album, Phytolacca americana, Barbarea vulgaris, Lepidium apetalum, Robinia pseudo-acacia, Trifolium repens, Erigeron annuus, Erigeron canadensis, Senecio vulgaris, Xanthium strumarium) was recorded in all study areas. Distribution of naturalized plants were categorized into 7 habitat types based on ecological traits: afforested land, beach, port, and vacant land, road boundary, road cut and slope area, waste arable land, landfill area, and wetland. Systematic management is required to conserve unique landscape, species diversity, vegetation and ecosystem of Dadohae National Park. In order to manage the naturalized plants in Dadohae National Park, basic surveys are most needed to understand distribution and dispersal of naturalized plants communities based on ecological features of each habitat type.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.54-65
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• 2012

While fishery has been continuously suffering from deteriorating economic feasibility, the amount of the deposited marine litter has been increasing due to an increased number of marine leisure tourists which are caused by an improved quality of life and five-day work week. In addition, the fishery area has been reduced by the reclamation projects and it is being destroyed by marine pollution with a variety of contaminants coming from land and sea. To protect and improve fisheries in these poor conditions, Korean governments have implemented the submerged marine litter collection projects. However, previous research results on the marine environment and resources indicate that it requires a lot of time investment to achieve tangible results of such improvement. The 300 billion won marine environment and resource investigation project has been executed since July 2004 by Korean governments, which demands strategic approaches to obtain more effective and satisfactory results before the project expires in 2013. Ocean environment research institutes and governments need to cooperate each other to gain efficient and reasonable achievement by identifying and linking related projects. This study suggests that the marine environment and resources investigation projects should run parallel with the submerged marine litter collection projects on mutually agreed research items in the identical area of the ocean to obtain cost-effective improvement of marine environment and fishery conditions.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.27-37
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• 2010

Downdrag force develops when a pile is driven through a soil layer which will settle more than a pile. There is no obvious criterion for application of the current pile design method considering the negative skin friction. Therefore, in this study, numerical analyses were performed to investigate the behavior of a single pile subjected to negative skin friction and their results were used to determine the applicability of the current design method. Including three different sites in Song-do area and two different cases with friction pile and end bearing pile conditions, total six cases were considered. The load-settlement relationships and the neutral points were estimated for different end bearing conditions and the allowable bearing capacity of piles with negative skin friction was investigated through parametric studies. Based on the results showed that the negative skin friction made a major influence on the settlement of a pile and its stress. However the allowable bearing capacity may not be influenced by the negative skin friction. Compared with the allowable bearing capacity obtained from the ultimate bearing capacity with the safety factor of 3, the current design method with the safety factor of 3 underestimated the allowable bearing capacities regardless of the end bearing conditions. On the other hand, the current design method with the safety factor of 2 yielded reasonable results depending on the end bearing conditions.