• Journal of the Korean Geosynthetics Society
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• v.6 no.1
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• pp.17-25
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• 2007

This study presents a modeling approach for geogrid-encased stone column(GESC) method which is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquefaction resistance, among others. Recently, geosynthetic-encased stone column approach has been developed to improve load carrying capacity through increasing confinement effect. The aim of this research is to establish a systematic approach for modeling of GESC and to form a database for the fundamentals of GESC. This paper presents details of 3D modeling of GESC together with the general behavior of GESC.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.387-402
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• 2014

In congested urban areas, constructions of tunnel structures have became necessary due to a lack of surface space. The excavation of any tunnel generated the ground disturbances of surrounding ground and displacements is major concern. Therefore, a study of tunnel stability is necessary. In this study, the authors have investigated the stability and failure pattern of tunnel through the model tunnel test. In this study, the close range photogrammetry was used to measure the ground deformation. The measured data was converted to displacement vectors and contours. And then it compared to FE analysis and empirical formula. In addition, this study presented the comparison between steel pipe reinforced model tunnel and unreinforced model tunnel. The ground deformation for both the steel pipe reinforced model tunnel and the unreinforced model tunnel was analysed.

• International Commerce and Information Review
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• v.14 no.2
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• pp.369-387
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• 2012

Throughout intensive negotiations on the KORUS FTA and even after its ratification on March 15, 2012, ISD (Investor-State Dispute Settlement) has been at the center of many controversies within the FTA. Although the original function of the ISD is intended to be a protectional measure for foreign investors, there have been many foreign investors who tried to use the ISD as a tool to attack a government and nullify the public policy demanding tremendous amount of compensation. Many of the NAFTA ISD cases including Ehtyl v. Canada and UPS v. Canada demonstrate such a behavior by foreign investors. It is the right time for Korean government to conduct in depth studies on NAFTA ISD cases because the precedents provide invaluable insights including the legal reasoning by the decision making authorities including ICSID and UNCITRAL. The lessons we would learn from those cases would prepare Korean government for expected ISD claims by foreign investors and enable the government to maximize its efficiency in policy making process under a new international trade environment, the KORUS FTA.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.202-211
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• 2016

This study aims to analyze seismic responses of suction foundations for offshore wind turbine. For this purpose, dynamic centrifuge model tests were carried out. The skirt length of the suction foundation is a critical element for bearing mechanism against environmental loads. Thus, dynamic centrifuge model tests were performed and analyzed for three suction foundation models with the ratios of skirt length to suction foundation diameter of 0.5, 0.75, and 1 installed in dense sand. As results, the acceleration amplification at the suction foundation, residual settlement, and residual tilting angle were compared.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.3-10
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• 2010

Case study was carried out on the interpretation of the mechanical behavior of a severely damaged reinforced earth wall comprising geotextile with the concrete panel facing. In this part I, the outline of the damaged reinforced earth wall is in detail described. The background and cause of the damage are discussed based on the results of site investigation. The engineering properties of the fill were examined by performing various in-situ and laboratory tests, including the surface wave survey (SWS), PS-logging, RI-logging, soaking test, the direct shear box (DSB) test, bender element (BE) test, etc. The background as well as the cause for the damage of the wall may be described such that i) a considerable amount of settlement took place over a 3m thick weak soil layer in the lower part of the reinforced earth due to seepage of rainfall water, ii) the weight of the upper fill was partially supported by the geo-textile hooked on the concrete panels (n.b., named conveniently "hammock state" in this paper), and iii) the concrete panels to form the hammock were severely damaged by the unexpectedly large downwards compression force triggered by the tension force of the geotextile. The numerical simulation for the hammock state of the wall, together with counter-measures to re- stabilize the wall is subsequently described in Part II.

• Journal of the Korean Geosynthetics Society
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• v.5 no.2
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• pp.45-50
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• 2006

Although the discharge capacity of the natural fiber drains are very low compared to that of plastic drain board (PDB), it is found that the conventional fiber drains and the new developed straw drain boards have great potential for use as a substitute for conventional plastic drain boards through several model tests. To verify their field application, a pilot test using environmentally friendly drains is also being carried out to prove their effective discharge capacity in the field. The pilot test site was divided into 5 different areas, with various combinations of vertical and horizontal drains installed for evaluation. Definite characteristics of various drains are still to be found due to the delay in construction of embankment. Consolidation behavior of three types of vertical drains and two types of horizontal drains will be analyzed after the completion of the embankment in the near future.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.13-23
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• 2019

In this study, an overtopping model experiments and three dimensional seepage characteristics at the deteriorated homogeneous reservoirs were performed to investigate the behavior of failure for embankment and spillway transitional zone due to overtopping. The failure pattern, pore water pressure, earth pressure and settlement by overtopping were compared and analyzed. The pattern of the failure by overtopping was gradually enlarged towards reservoirs crest from the spillway transition zone at initial stage. In the rapid stage and peak stage, the width and depth of failure gradually increased, and the pattern of the failure appeared irregular and several direction of the erosion. In the early stage, the pore water pressure at spillway transitional zone was more affected as its variation and failure width increased. In the peak stage, the pore water pressure was significantly increased in all locations due to the influence of seepage. The earth pressure increased gradually according to overtopping stage. The pore pressure by the numerical analysis was larger than the experimental value, and the analysis was more likely to increase steadily without any apparent variation. The horizontal and vertical displacements were the largest at the toe of slope and at the top of the dam crest, respectively. The results of this displacement distribution can be applied as a basis for determining the position of reinforcement at the downstream slope and the crest. The collapse in the overtopping stage began with erosion of the most vulnerable parts of the dam crest, and the embankment was completely collapsed as the overtopping stage increased.

• Geomechanics and Engineering
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• v.28 no.6
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• pp.547-557
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• 2022

Dune sands are poorly graded collapsible soils lacking fines. This experimental study explored the technical feasibility of sustainable invigoration of fine waste materials to improve the geotechnical properties of dune sand. The fine waste considered in this study is fine marble waste. The fine waste powder was mixed with dune sand at different contents (5, 10,15, 20, 25, 50%), where the gradation, void ratio, compaction, and shear strength characteristics were assessed for each fine marble waste -dune sand blend. The geotechnical properties of the dune sand-fine marble waste mix delineated in this study reveal the enhancement in compaction and gradation characteristics of dune sand. According to the results, the binary mixture of dune sand with 20% of fine marble waste gives the highest maximum dry density and results in shear strength improvement. In addition, a numerical study is conducted for the practical application of the binary mix in the field and tested for an isolated shallow foundation. The elemental analysis of the fine marble waste confirms that the material is non-contaminated and can be employed for engineering applications. Furthermore, the numerical study elucidated that the shallow surface replacement of the site with the dune sand mixed with 20% fine marble waste gives optimal performance in terms of stress generation and settlement behavior of an isolated footing. For a sustainable mechanical performance of the fine marble waste mixed sand, an optimum dose of 20% fine marble waste is recommended, and some correlations are proposed. Thus, for improving dune sand's geotechnical characteristics, the addition of fine marble waste to the dune sand is an environment-friendly solution.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.7-22
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• 2021

In this study, inverse analysis was performed on the bi-directional axial compressive load test conducted on drilled shafts. And the bearing capacities were analyzed by numerical analysis of various pile tip ground conditions of silt clay, silt sand, sand silt, sand gravel, weathered rock, and soft rock. The bearing capacities were analyzed using the P-S method, the Davisson method, and the allowable sttlement of 25.4 mm. The minimum allowable bearing capacities analyzed by three methods were found to be 19.64 MN ~ 24.96 MN. At this time, the base resistances were sharing a 2% ~ 12% of a head load, shaft resistance were shared 88% ~ 98% of the head load. The greater the strength of pile tip was found to increase the allowable bearing capacity. However, the difference between the maximum allowable bearing capacity and the minimum allowable bearing capacity was 5.32 MN, and the increase in the allowable bearing capacity was only 27% depending on the pile tip.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.320-326
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• 2022

The use of the Internet has become commonplace for billions of people on the planet. The rapid development of technology, in particular, mobile gadgets, has provided access to communication anywhere, anytime. At the same time, there are growing concerns about the behavior of people on the Internet, in particular, towards each other and social groups in general. This raises the issue of human rights in today's information society. In this study, we focused on human rights such as the right to privacy, confidentiality, freedom of expression, the right to be forgotten, etc. We point to some differences in this regard, in particular between the EU, etc. In addition, we describe the latest legal regulation in this aspect in European countries. Such methods as systemic, factual, formal and legal, to show the factors of formation and development of human rights in the context of digitalization were used. The authors indicate which of them deserve the most attention due to their prevalence and relevance. Thus, we concluded that the technological development of social communications has laid the groundwork for a legal settlement of privacy and opinion issues on the Internet. Simultaneously, jurisdictions address issues on every aspect of human rights on the Internet, based on previous norms, case law, and principles of law. It is concluded that human rights legislation on the Internet will continue to be actively developed to ensure a balance of private and public interests, safe online access and unimpeded access to it.