• 한국환경과학회지
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• 제25권5호
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• pp.715-726
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• 2016

This study investigates the characteristics of metallic and ionic elements concentration, concentration according to transport path, and factor analysis in $PM_{10}$ at Guducsan in Busan in the springtime of 2015. $PM_{10}$ concentration in Guducsan and Gwaebeopdong were $59.5{\pm}9.04{\mu}g/m^3$ and $87.5{\pm}20.2{\mu}g/m^3$, respectively. Contribution rate of water-soluble ions and secondary ion in $PM_{10}$ concentration in Guducsan were 37.0% and 27.8% respectively. [$NO_3{^-}/SO{_4}^{2-}$] ratio and contribution rate of sea salt of $PM_{10}$ in Guducsan and Gwaebeopdong were 0.91 and 1.12, 7.0% and 5.3%, respectively. The results of the backward trajectory analysis indicates that $PM_{10}$ concentration, total inorganic water-soluble ions and total secondary ions were high when the air parcels moved from Sandong region in China than non-Sandong and northen China to Busan area. The results of the factor analysis at Guducsan indicates that factor 1 was anthropogenic source effects such as automobile emissions and industrial combustion processes, factor 2 was marine sources such as sea salts from sea, and factor 3 was soil component sources.

• 한국환경복원기술학회지
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• 제13권1호
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• pp.47-56
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• 2010

The main objectives of this comparative study were 1) to quantify the potential contribution of wood chips to revegetation on the cut slope in a constructed area, 2) to compare the floristic similarity of species composition whether existing of wood chips in the soil media or not. Wood chips were combined with soil media in the ratio of 30%. The thin layer (1 cm, 3 cm) soil media revegetation methods and the thick layer (10 cm) soil media revegetation method were constructed on the cut slopes by machineries respectively. Also, comparative experiments the existence of wood chips in the soil media were conducted to evaluate the effects of wood chips on revegetation works. The total size of quadrat was $300m^2$ ($100m^2{\times}3$). The results of monitoring for 3 years on cut slopes were as follows: 1) All the quadrat existed in the proper range for vegetation. 2) Species richness of quadrat including wood chips was 10% more than those of commercial soil medias. 3) The coverage rates of quadrat including wood chips were similar or superior to those of conventional methods. It can be concluded that the use of wood chips would be effective to promote establishment of diverse landscape and vegetation. However, it behooves to continue monitoring on succession of vegetation for ecological restoration. Finally, adequate wood chips deposit and gathering methods should be studied properly.

• 한국토양비료학회지
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• 제44권4호
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• pp.662-666
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• 2011

In this study, distribution characteristics of dioxins in soils in Busan, Korea were investigated regarding different land use types. Soil sampling sites that distributed through the Busan city showed dioxin concentration ranging from 0.489 to $322.736pg-TEQ\;g^{-1}$ dry weight with a mean value of $26.257pg-TEQ\;g^{-1}$ dry weight. The mean dioxin concentrations of investigated soils ranged from 1.554 to $50.357pg-TEQ\;g^{-1}$ dry weight in consideration of each land use type. That in metal refinery sites with $50.357pg-TEQ\;g^{-1}$ dry weight was higher than any other sites, followed by waste incinerator sites with $44.285pg-TEQ\;g^{-1}$ dry weight. The majority of soil samples had the same dioxin congener profiling despite the different range of dioxin concentration. Octa-CDD was the major contributor among seventeen dioxin congeners with the range from 29.5 to 70.1% in real values. In contrast to real values, dioxin congener profiles in TEQ values were dominated by 2,3,4,7,8-PeCDF which contributed about 35.3~43.8% to the total dioxin concentrations. It was judged by these results that penta-CDF was the major contributor of soil samples in Busan city. The mean ratio of PCDFs/PCDDs in real values was about 0.71, but that in TEQ values was, in contrast to it, approximately 3.03.

• 한국토양비료학회지
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• 제45권1호
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• pp.107-111
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• 2012

Eight marine sediments from Busan port in Korea were annually analyzed to examine the concentration distribution of dioxins from 2006 to 2010. Yearly mean concentration of dioxins ranged from 186.3 to $383.3pg\;g^{-1}$ in real values and 5.087 to 8.541 pg-TEQ (Toxicity equivalency) based on dry weight of samples. The dioxin concentration at the site near fishing market was the highest concentration among all sampling sites. Also the dioxin concentration at the sites with various pollutant sources such as large ships, sewage influx and thermal power station as well as fishing market was higher than that of the sites without specific pollutant sources. Another main factor that affects the dioxin concentration is topography characteristics of the bay. The bay has relatively high dioxin concentration because of the lack of the pollutant diffusion. This study demonstrated that the dioxin concentration in the site with pollutant sources and the lack of the pollutant diffusion was relatively high as compared with the other sites. As a result of contribution ratio of dioxin congeners, OCDD (Octachlorodibenzodioxin) in all sites was major contributor in real value, in contrast, dioxin congeners in TEQ values were dominated by 2,3,4,7,8-PeCDF.

• Geomechanics and Engineering
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• 제21권5호
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• pp.401-411
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• 2020

The paper describes the influence of pile reinforcement on the stability of the slope behaviour, and the exploitation of the results of in situ measurements will be conducted. In the second part, a 2D numerical modelling will be conducted by using the finite element code PLAXIS2D; in order to validate the proposed modelling approach by comparing the numerical results with the measurements results carried out on the slides studied; to study the effect of positioning of piles as a function of the shear parameters of the supported soil on the behaviour of the soil. For various shear strength of the soil a row of pile position is found, at which the piles offer the maximum contribution to slope stability. The position of piles is found to influence the safety factor in granular soil whereas it shows a slight influence on the safety factor in coherent soil. The results also indicate that the ideal position for such stabilizing piles is in the middle height of the slope. Comparison of results of present study with literature from publication: indicated that to reach the maximum stability of slope, the pile must be installed with L_x/L ratio (0.37 to 0.62) and the inclination must be between 30° to 60°. Even, after a certain length of the pile, the increasing will be useless. The application of the present approach to such a problem is located at the section of PK 210+480 to 210+800 of the Algerian East-West Highway.

• 한국농공학회지
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• 제32권4호
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• pp.71-80
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• 1990

Model tests for the ultimate pullout resistance of anchorages and investigation of failure behaviors in cohesionless soil have been conducted. The factors affecting the anchorage are mostly the geometry of the system, and soil properties of sands. The main conclusions of the experimental work were as follows. 1. The load - displacement relationship can be a form of parabolic curve for all plates. 2. The change in ultimate pullout resistance of anchor is mostly affected by embedment ratio and size of anchor, and influenced to a lesser degree by its shape. 3. Critical embedment ratio which is defined as the failure mode changes from shallow to deep mode is increased with increasing height of anchor. 4. For a constant anchor height, as the width of anchor increases the ultimate pullout resistance also increases. However, considering the efficiency of anchor for unit area, width of anchor does not appear to have any sigrnificant contribution on increasing anchor city. 5. Anchor capacity has a linear relation to sand density for any given section and the rate of change increases as the section increases. Critical depth determining the failure patterns of anchor is decreased with a decrease of sand density. 6. With increasing inclination angle, size of anchor, and decreasing embedment ratio, the ultimate pullout resistance of anchor under inclined loading is significantly decreased. 7. The ultimate pullout resistance of double anchor, a method of improving single of anchor capacity, is influenced by the center - to - center spacing adjacent anchors. It is also found that tandem and parallel anchor rigging arrangements decrease the anchor system capacity to less than twice the single anchor capacity due to anchor interference.

• Geomechanics and Engineering
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• 제5권3호
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• pp.187-194
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• 2013

The most soil anchor works have been concerned with the uplift problem on embedded in non-reinforced soils under pullout test. Symmetrical anchor plates are a foundation system that can be resisting tensile load with the support of around soil in which symmetrical anchor plate is embedded. Engineers and authors proved that the uplift response can be improved by grouping the symmetrical anchor plates, increasing the unit weight, embedment ratio and the size of symmetrical anchor plates. Innovation of geosynthetics in the field of geotechnical engineering as reinforcement materials found to be possible solution in symmetrical anchor plate responses. Unfortunately the importance of reinforcement in submergence has received very little attention by researchers. In this paper, provision of tensile reinforcement under embedded conditions has been studied through uplift experiments on symmetrical anchor plates by few researchers. From the test results it has been showed that the provision of geogrid reinforcement system enhances the uplift response substantially under uplift test although other results are such as increase the ultimate uplift response of symmetrical anchor plate embedded using geosynthetic and Grid Fixed Reinforced (GFR) and symmetrical anchor plate improvement is very dependent on geosynthetic layer length and increases significantly until the amount of beyond that further increase in the layer length does not show a significant contribution in the anchor response.

• 대한지하수환경학회지
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• 제6권3호
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• pp.107-110
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• 1999

제주도 지하수중 질산염농도가 높은 지점을 선정하여 1995년부터 1996년까지 4차에 걸쳐 질소안정등위원소의 자연존재를 측정하고. 오염원별 기여율을 계산한 결과는 다음과 같다. 화학비료에 의한 영향이 뚜렸하게 나타나는 지점은 T-3, L-1. O-1∼O-4. F-2∼F-5. G-2의 11개소로써 화학비료 질소성분이 지하수 질산염농도 중 약 60% 이상을 차지하는 것으로 조사되었다. 그리고. 동물성 유기물질에 의한 영향이 많은 지하수는 T-4, T-5. G-2지점 3개소이며, T-4, T-5지점은 생활하수에 의한 영향으로, G-2지점은 쓰레기매립장 침출수의 영향으로 사료된다. 또한. 화학비료와 동물성 유기물질에 의한 영향을 비슷하게 받는 지하수는 T-1, T-2. L-2. F-1지점 4개소로 조사되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 기초기술위원회 워크샵
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• pp.102-117
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• 2002

The general design practice for piled footings is based on the assumption that the piles are free-standing, and that all the external loads are carried by the piles, with any contribution of the footing being ignored. This approach is not reasonable, because the footing itself is actually in direct contact with the soil, and thus carries a significant fraction of the loads. In the case of not considering the bearing capacity of footing, the bearing capacity of group piles can be evaluated conservatively in the designing the group piles. There are a number of reasons why the idea of piled raft design with considering the capacity of footing has not become widely used. One of the reasons is the lack of reliable calculation methods for estimating the behavior of piled raft. In this study the bearing capacity, settlement, load distribution, etc. of piled raft footing are studied.

• 한국환경보건학회지
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• 제36권2호
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• pp.108-117
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• 2010

In this study, ambient particulate matter ($PM_{2.5}$ and $PM_{10}$) levels were measured and their chemical and physical properties were characterized. Two sites in Gwangju were sampled once a month from December 2008 to November 2009. The annual mean concentrations of $PM_{2.5}$ and $PM_{10}$ were $26.9\;{\mu}g/m^3$ and $46.3\;{\mu}g/m^3$, respectively, in Nongseongdong and $26.1\;{\mu}g/m^3$ and $44.8\;{\mu}g/m^3$, respectively, in Duam-dong. $PM_{2.5}$ levels were 1.8 times higher than the USA Environmental Protection Agency (EPA) national ambient air quality standard for $PM_{2.5}$ ($15\;{\mu}g/m^3$). The average $PM_{2.5}/PM_{10}$ ratio of 0.58 suggested that $PM_{2.5}$ is a significant component of the ambient particle pollution. The order of concentration of metallic elements in $PM_{2.5}$ and $PM_{10}$ was Si > Al > Fe > Zn > Pb > Cu > Mn. Cd was not detected. The earth crustal enrichment factors for Cr, Cu, Pb and Zn in $PM_{2.5}$ were higher than those in $PM_{10}$. When the earth crustal enrichment factors for Cr, Cu, Pb and Zn were higher than 10, this suggested influence from anthropogenic sources. The soil contribution ratios for $PM_{2.5}$ and $PM_{10}$ were 11.3% and 16.4%, respectively, and were higher in the fall and winter. Anions (${SO_4}^{-2}$, ${NO_3}^-$, and $Cl^-$) comprise 28.7% of $PM_{2.5}$ and 21.4% of $PM_{10}$. The correlation coefficient of Zn-Fe, Mn-Cu, Fe-Cu and Fe-Mn in $PM_{2.5}$ was high in the sampling sites, and metallic elements were primarily from anthropogenic sources such as fuel combustion and vehicle emissions.