• International Journal of Highway Engineering
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• v.1 no.1
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• pp.107-119
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• 1999

The joints in the jointed concrete pavement provide a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random cracks cause more serious distresses and result in structural or functional failure of pavement system. However, joints nay cause distresses due to its inherent weakness in structural integrity. Thus, the evaluation at joint is very important. and the joint-related distresses should be evaluated reasonably for economic rehabilitation. The purpose of this paper was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis program, ILLI-SLAB, and nondestructive testing device. FWD. To develop an evaluation system for JCP, a sensitivity analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. An evaluation charts were made for jointed concrete pavement by adopting the field FWD data. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP are 300pci. 500,000 lb/in. respectively. Using these variables and FWD test, a charts of load transfer ratio versus surface deflection at joints were made in order to evaluate the performance of JCP. Practically, Chungbu highway was evaluated by these evaluation charts and FWD field data for jointed concrete pavement. For Chungbu highway, only one joint showed smaller value than limiting criterion of the modulus of dowel/concrete interaction(G). The rest joints showed larger values than limiting criteria of the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G).

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.605-618
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• 1996

Namsan area supposed to be a disturbed ecosystem and Kwangneung area considered to be a natural ecosystem were selected for the study. On the basis of the plant species composition, the study was planned to examine structural plant species diversity so as to provide basic ecological information to restore more stable and healthy ecosystem for Namsan. The stratified sample plot method was employed for collecting vegetation data, establishing $20m{\times}20m$ square plots for overstory trees, $4m{\times}4m$ plots for mid-story woody plants, and $1m{\times}1m$ plots for ground vegetation. The herbaceous plants were periodically investigated by taking into account for seasonal(spring, summer, and autumn) variation in presence. Ecological attributes were evaluated through analyzing species composition, species diversity, life forms, interspecies association, and growing habitat for various forest types, vertical layers, life forms, and seasonal variation. Even though the species diversity index of canopy trees in the deciduous forest of Namsan was estimated higher than that of the natural forest of Kwangneung, overall species diversity of plants in Kwangneung area was greater than that in Namsan area. Herbaceous plants presented in Kwangneung but not in Namsan were Aconitum pseudo-proliferum, Botrychium virginianum, Dryopteris tokyoensis, Scutellaria insignis, Tricyrtis dilatata, and Viola kamibayashii, most of them were endemic species of Kwangneung. Elaeagnus umbellata, and Prunes padus var. seoulensis were found only in Namsan. Such species typically composed of the natural deciduous forest as Acer mono, Acer triflorum, Carpinus laxiflora, Cornus controversa, Fraxinus mandshurica, and Phellodendron amurertse were limited growing in a small size of area in Namsan. The future project should be made for encouraging the growth and expansion of the distribution of such species to restore biodiversity in Namsan area.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.165-172
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• 2012

In this study, the physical, mechanical, structural, and environmental performances based on field measured data were evaluated to check the suitability of concrete for ecological preservation and cultivation of a hydrophilic environment. More specifically, the study is focused on developing an environmentally friendly functional concrete with river ecology restoration and natural river early formation capabilities. The mechanical performance evaluation results showed that the increase in mix rate of the PVA (Poly Vinyl Alcohol) reinforcement fibers and silica fume caused an increase in the strength. The optimal mix rate was found to be 0.05 volume % PVA fiber and approximately 10% silica fume. The frost resistance evaluation showed that superior performance was gained when 0.05 volume % PVA fiber and 15% silica fume was mixed simultaneously. In the structural performance evaluation, the bending strength was improved by 47.7% compared to plain concrete when mixed with 0.05 volume % PVA fiber. The flexural toughness also saw significant improvement. The environmental monitoring of field performance showed that grasses germinated most rapidly, but the growth of red poppies, a plant that germinates in the spring, was most active with passing of time. Coverage measurements in all of the monitoring locations found favorable coverage of over 95% after 12 weeks. The study results showed that the environmentally friendly functional concrete had outstanding environmental performance.

• Korean Journal of Environment and Ecology
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• v.35 no.2
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• pp.204-219
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• 2021

This study was conducted to investigate and analyze the characteristics of the plant community structure of vegetation distributed on the western slope and ridge connecting Mt. Noja to Mt. Gara. This basic research was executed not only to restore and manage forest vegetation, but also to monitor the trend of change in the long term. As a result of classifying the communitise in 86 survey quadrats, the Pinus thunbergii-Platycarya strobilacea comm. and P. thunbergii-P. densiflora comm. were distributed around the lowlands. The Carpinus tschonoskii-Deciduous broad-leaved comm., Styrax japonicus-Deciduous broad-leaved comm., Acer pictum subsp. Mono-Deciduous broad-leaved comm., Deciduous broad-leaved comm., and Zelkova serrata comm. appeared in the valley and all stone areas. Quercus serrata comm., Q. serrata-S. japonicus comm., S. japonicus-Carpinus cordata comm., Euonymus oxyphyllus comm. were classified as being distributed on steep slopes with relatively high altitude. According to the succession trend of the forest, evergreen conifers will be transition to deciduous broad-leaved trees. However, deciduous broad-leaved arboreous forests, such as Carpinus tschonoskii, zelkova serrata, and Acer pictum subsp. Mono, were considered to maintain their current succession stage because not only the stratified structure was developed over about 50 years tree age, but also ecologically stabilized. As environmental factors, it was analyzed that altitude, pH, content of clay and silt, Mg⁺⁺, Ca⁺⁺, etc. directly or indirectly affect the distribution of plant communities.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1063-1069
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• 2007

우리나라의 하천환경은 1990년대 이전의 산업화와 인구증가를 수반한 고도성장기를 거치면서 이수성 및 치수성만을 강조하며 개수되고 관리되었다. 그 결과 하천은 획일적인 단면과 저수로 및 제방이 콘크리트화되면서 하천의 자정능력은 감소되었고, 하천을 중심으로 생활하는 동물들의 서식처 기능을 상실해 하천생태계가 위협받고 있다. 하천공사에 자연형 하천공법이 도입되기 시작하여 자연형 하천공사가 이루어지고 있지만 생태환경의 관점보다는 조경 및 경관적, 그리고 위락적인 관점에서 공원화에 주안점을 두고 있어 하천의 생태적 특성의 반영이 부족하다는 평가를 듣고 있는 실정이다. 따라서 본 연구에서는 향후의 하천공법이 자연적 기능들 중 생물서식처 기능을 보다 깊이 다루어야 한다는 필요성을 고려하여, 먹이사슬의 최상위에 있을 뿐만 아니라 하천환경의 건강도를 판단할 수 있는 수환경의 지표종이라 불리는 수달(Lutra lutra)을 대상으로 배설물에 의한 출현빈도와 하천환경 요인들에 대한 상관관계를 분석하여 수달 서식지 복원을 위한 하천정비의 기초자료를 제공하는 데 그 목적이 있다. 이를 위해 현재 수달이 서식하고 있는 섬진강 지류인 서시천을 연구 대상지점으로 하여 5개 구간을 선정하였으며, 각 구간에 대한 계절별 수달의 배설물 분포를 조사하여 출현빈도를 나타내었다. 또한 먹이, 지형, 식생, 기상인자를 포함한 하천환경 요인들에 대한 자료를 각 계절별로 구축하였으며, 이를 수달의 출현빈도와의 상관관계를 조사하는데 활용하였다. 본 연구의 결과는 환경 기술적으로는 멸종위기종의 복원, 사회경제적으로는 하천정비사업의 방향제시 등의 기대효과를 가져올 수 있으리라 생각되며 분석된 인자들은 수달 서식지를 위한 하천정비의 기초자료에 유용할 것으로 보인다.따른 유량측정망을 구축하는 것이다.의 의사결정 지원 도구가 될 것이다. 따라서, 본 연구에서는 도시유역의 물순환 해석을 위한 일련의 과정, 즉 자료의 조사 및 취득에서부터 물순환 해석 모형을 이용한 정량적 현황파악, 물순환 개선 기법 및 평가를 수행함에 있어 주요 착안점 및 실무에서의 기술적 가이드를 제공하고자 하였으며, 보다 세밀한 도시유역의 물순환 해석을 위하여 우리나라와 일본에서 적용이 활발한 물리적 기반의 분포형 모형(WEP, SHER, SWMM)의 적용사례를 통하여 국내 도시하천의 물순환 해석에 활용함에 있어서의 실질적인 적용절차 등을 제시하고자 하였다. 한다.호강유역의 급격한 수질개선을 알 수 있다.世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와 동년대에 동일한 목적으로 찬술되었음을 알 수 있다. $\ulcorner$경상도실록지리지$\lrcorner$(慶尙道實錄地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.222-228
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• 2012

This study was conducted to determine the natural succession process after forest fire by comparing height, relative growth rates in height (RGH), and tree density of pine seedlings with different fire severity. In the area damaged by surface fire, tree density was highest during the first 5 years after fire. However, in the area damaged by crown fire, tree density rapidly increased during first 5 years after fire. Pine seedlings were found only on the place with ridges, barren soil, and the aspect of north. Annual height growth of pine seedlings was decreased with time in all study sites. The empty space in pine stands gradually decreased by the invasion of Quercus species. The forest fire altered the pine forest into oak forest rapidly. In contrast, pine seedlings invaded steadily on the oak forest in the rocky area or the area with ridges.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.37 no.2
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• pp.20-29
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• 2019

The purpose of this study is to verify and reconstruct the record information for big old trees of Jeju on the basis of the precise map of Jeju island in 1918 which was produced 100 years ago. For the analysis of high altitude, coordinate system and georeferencing were performed by selecting representative points using ArcGIS. We extracted digitized information by using point extraction method and extracted attribute information based on legend type and relative size in map. Based on the map of the past 100 years ago, the present situation of the big old tree in Jeju was analyzed and their characteristics were analyzed. In addition, based on the information of the protected big old trees in present, we discussed the characteristics of past tree (1918), present tree (2019), and contribution of big old tree in Jeju landscape and vegetation. As a result, 1,013 individuals were distributed in Jeju Island 100 years ago. Even when it was intensive in the use of timber, the big old trees were protected, and contributed as a representative component of Jeju's unique landscape. The remaining distribution of Jeju's big old tree is 159 trees. As in the past, distribution has been confirmed around the lowlands, but declines in numbers are found throughout the island. The major factors for the decline of individuals are large-scale development projects such as reaching the limit of life, natural disturbance (typhoon, disease, pest, drought, etc.). However, it is presumed that a large number of individuals have played a leading role in shaping the current forests as contributing to important species sources in the restoration process of Jeju vegetation. However, it is presumed that a large number of individuals (405) have played a leading role in forming the present forest by contributing to the species pool in the restoration process of Jeju vegetation.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.53-62
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• 2002

The physical and chemical properties of cover soils of 10 waste landfill sites in Kyonggi-Do area, where social circumstances at present forces to consider the reuse of landfill, were investigated to provide the informations of soil environment which are necessary to establish the appropriate ecological restoration plan of waste landfills. The pH and electrical conductivity of soils were higher in landfills sites than in reference sites (area around landfill sites), indicating the salt accumulation in surface soil. However, total-N and organic matter contents were lower in landfills sites than in reference sites. In landfill sites, the total-N and plant available-P contents were less than 0.15% and 20mg/kg, respectively. Exchangeable cations (K, Ca, Mg and Na) and heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) contents varied between the landfill sites, but were higher in landfills sites than in reference sites. The major exchangeable cation of soil was Ca. Heavy metal contents were much lower than the critical concentration which phytotoxicity is considered to be possible and the standard for agricultural land of Korean Soil Environmental Preservation Act. Therefore, the proper soil management plan to increase the soil fertility is recommended for the ecological restoration of landfill using natural or artificial vegetation.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.191-201
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• 2021

Rivers have been damaged due to rapid urbanization, and river management has been carried out focusing on flow and flood control functions. Recently, interest in river restoration, emphasizing the environmental aspects of rivers, is increasing, but the beginning of river restoration requires an appropriate evaluation of the environmental flow required for the ecosystem. This study analyzed the effects on the habitat of the river ecosystem by estimating the changes in flow regime and environmental flow following the construction of the Buhang dam in Gamcheon, the first tributary of the Nakdong River. To evaluate the environmental flow, the dominant species of Gamcheon, Zacco Platypus, and the protected species Squalidus gracilis majime, and riparian vegetation were selected, and the environmental flow was calculated using the HEC-EFM (Ecosystem Function Model). The evaluated environmental flow was linked with hydraulic analysis and GIS platform, and habitat area change and habitat connectivity analysis before and after dam construction were performed by spatial habitat analysis in the river. Based on the results of this study, it can be used as a river restoration project and a dam operation plan considering the river environment through the calculation of environmental flow and habitat connectivity analysis to improve the habitat of the river ecosystem.

• Korean Journal of Environment and Ecology
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• v.33 no.3
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• pp.280-291
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• 2019

A. antiquum, first observed in Jeju Samdo Island in 1949, was designated as the Natural Monument No. 18 in December 1962 in recognition of its academic value. In Korea, it grows in nature only in Samdo in Jeju Island. Although its natural habitat was greatly damaged and almost destroyed due to firewood, stealing, etc. After the emancipation, it has been maintained by the transplantation and restoration. The site observed by this study has been managed as a restricted area since 2011. Since it has been about 20 years since the restoration of the native site in the 2000s, it is necessary to check the official management history records, such as the origin of transplantation and restoration to monitor the changes in the growth status and to control the habitat. As the results of this study, we have secured the records of cultural property management history, such as the identification of native species and the transplantation and restoration records. We also examined the change of the growth and development of A. antiquum 20 years after the restoration. There are no official records of the individuals transplanted to the restored natural habitat of A. antiquum in the 1970s and 1980s, and there was a controversy about the nativeness of those individuals that were restored and transplanted in 1974 since they were Japanese individuals. The studies of identifying native as the results of this study, we have secured the records of cultural property management history, such as the identification of native species and the transplantation and restoration records. We also examined the change of the growth and development of A. antiquum 20 years after the restoration. There are two sites in natural habitat in Samdo Island. A total of 65 individuals grow in three layers on three stone walls in a site while 29 individuals grow in two columns in the other site. A. antiquum grows in an evergreen broad-leaved forest dominated by Neolitsea sericea, and we did not find any other individuals of naturally growing A. antiquum outside the investigated site. This study checked the distribution of A. antiquum seedlings observed initially after the restoration. There were more than 300 seedling individuals, and we selected three densely populated sites for monitoring. There were 23 A. antiquum seedlings with 4 - 17 leaves per individual and the leaf length of 0.5 - 20 cm in monitoring site 1. There were 88 individuals with 5 - 6 leaves per individual and the leaf length of 1.3 - 10.4 cm in monitoring site 2 while there were 22 individuals with 5 - 9 leaves per individual and the leaf length of 4.5 - 12.1 cm in monitoring site 3. Although the natural habitat of A. antiquum was designated as a restricted public area in 2011, there is a high possibility that the habitat can be damaged because some activities, such as fishing and scuba diving are allowed. Therefore, it is necessary to enforce the law strictly, to provide sufficient education for the preservation of natural treasures, and to present accurate information about cultural assets.