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Vegetation Structure and Succession of the Decomposed Granite Cut-slope - In case study on forest road of Gangwon-do - (화강암질 풍화토 절토비탈면의 식생구조와 천이 - 강원도 임도를 중심으로 -)

  • Song, Ho-Kyung;Park, Gwan-Soo;Lee, Joon-Woo;Lee, Mi-Jeong;Lee, Sang-Hwa;Kim, Hyo-Jeong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.6
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    • pp.84-93
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    • 2004
  • This study was carried out to select proper species for early stage replantation in granite forest roads cut-slope. From two to sixteen year elapsed forest roads in four regional areas of Gangwon-do, sample plots were selected, and their vegetations and environmental factors were investigated. Soil organic matter, total nitrogen, soil moisture content, and bulk density in the decomposed granite soils were below 1.32%, 0.08%, 10.0%, and above 1.24g/cm3, respectively. The result indicated that the soil was not good for plant growth. The environmental factors affecting distribution of species in the granite forest roads were the elapsed year, cut-slope, elevation, and cut-slope aspect. Species with high frequency in the granite forest road cut-slope ordered Lespedeza bicolor, Rubus crataegifolius, Pinus densiflora, Lysimachia clethroides, Amorpha fruticosa, Dactylis glomerata, Lespedeza cyrtobotrya, Festuca arundinacea, Spodiopogon sibiricus, Artemisia stolonifera, and Weigela subsessilis. Herbs seeded in earth stage such as Dactylis glomerata, Lolium perenne, and Festuca arundinacea had changed into perennial herbs such as Carex lanceolata, Poa sphondylodes, Patrinia villosa, Artemisia princeps var. orientalis, Spodiopogon sibiricus, Melica onoei, Artemisia keiskeana, Artemisia stolonifera, Astilbe chinensis var. davidii, Spodiopogon sibiricus, and those had changed into shrubs such as Rubus crataegifolius and Weigela subsessilis, and those had changed into trees such as Salix hulteni, Salix koreensis, and Fraxinus rhyncholhylla according to elapsed year of forest roads. Legumes such as Lespedeza sp., Pueraria thunbergiana, Amorpha fruticosa, etc., herbs such as Artemisia keiskeana, Artemisia princeps var. orientalis, Artemisia stolonifera, Astilbe chinensis var. davidii, Spodiopogon sibiricus, Miscanthus sinensis, etc., and woody plants such as Pinus densiflora, Rubus crataegifolius, Weigela subsessilis, Zanthoxylum schinifolium, Rhododendron mucronulatum, etc., with foreign herbs were considered as proper species for replantation in granite forest road cut-slope.

A Study on the Historical Landscape of Dongrae Ciy-wall in Busan (조선-일제강점기 동래읍성 경관변화 연구)

  • 김기혁;김성희
    • Journal of the Korean Geographical Society
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    • v.37 no.4
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    • pp.317-336
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    • 2002
  • Dongrae-bu, the administrative central area in Busan in Chosun-dynasty(1392-1910), performed the large parts of diplomatic and trading functions with Japan because of its geographical conditions. Because of his location, landscape of Dongrae city-wall is the mirror of political and military meaning in Chosun-dynasty period. Elements of landscape, such as site of city-wall, location and morphology of gates, government official buildings and the road systems can be interpreted by the functional and socio-cultural terms. The changes of landscape during Japanese colonial period(1910-1945) show that destruction of city-walt went on for the purpose of imperialism. Especially, the landscape which had political meaning in Chosun-dynasty had erased in terms of modem urban planning. Cates of city-wall, official guest house, fortress which symbolize the governing and political power of Chosun-dynasty were destructed almost perfectively. New road system was imported Urban planning was effective instrument through which city-wall could be destroyed for the Japanese colonialism. Under those processes, traditional structure was changed towards the dependency on Japan. Those relict landscape are remained in present urban landscape such as road system, cul-de sac, house and cornerstones. Those results of this study show that city-wall in Korea should be studied in terms of socio-cultural aspects in each periods.

Hypothesis Tests on the Relations Between Interchange Types and Traffic Accidents in the Case of Korean Expressways (고속도로 교차점 유형과 교통사고의 가설검정)

  • Park, Byeong-Ho;Ryu, Seung-Ok;Park, Jeong-Sun;Han, Sang-Uk
    • Journal of Korean Society of Transportation
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    • v.25 no.6
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    • pp.55-63
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    • 2007
  • This research deals with the relations between intersection types and traffic accidents in the case of Korean expressways. The purpose of this research is to test the hypotheses that traffic accidents depend on intersection types and geometric design elements. The main research results are as follows. First, the accident comparisons that are drawn from junctions with interchanges, and trumpet interchanges with other types of interchanges respectively displays no significant meaning. However, the differences among four types of trumpet interchanges are found to be meaningful. In other words, the BO type trumpet interchanges seem to have far more traffic accidents than other types of trumpet interchanges. Second, hypothesis tests show that approximately 90 degree and one lane connection roads have lower accident rates. Based on this research, the following directions can be suggested for the safer types of intersections and geometric design elements in freeway construction. From a road safety point of view, it is advisable not to introduce BO type interchanges. It is also desirable that the intersection angle should be approximately 90 degrees. Furthermore, it would be wise to design one lane roads if the connection road has low traffic volumes.

Development of DCPT Equipment based on IoT for Rod Tamping in Smart Construction (스마트건설 토공사 다짐 측정을 위한 IoT 기반의 DCPT 기술개발)

  • Park, Hong-Gi;Bae, Kyoung-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.11
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    • pp.501-509
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    • 2020
  • Earthwork in the construction field is a core process of construction, and it is used in almost all processes and is connected to the safety of the structure directly. Therefore, it is essential to analyze and confirm the road tamping through a plate bearing test and a field density test. The current analog measurement methods for road tamping measurement is difficult to check in real-time, accurate location information, time information, and the history management of workers in the field. Therefore, IoT (Internet of Things)-based DCPT (Dynamic Cone Penetration Test) was developed for a smart construction environment with a solution to the problem. The Smart DCPT system operated in a smartphone environment is IoT-based. The Smart DCPT system can apply various applications and has advantages of flexibility, low cost, and high efficiency. The IoT-based DCPT records the digital road tamping information, location information, time information, and worker information per measurement count. In addition, the various information is transmitted in real-time to the management center through a smartphone. This system is expected to contribute to the management of the construction process.

Comparing Laboratory Responses of Engineered Emulsified Asphalt and Foamed Asphalt Mixtures for Cold In-place Recycling Pavement (현장 상온 재생 아스팔트 포장을 위한 고점착 유화 아스팔트 혼합물과 폼드 아스팔트 혼합물의 반응특성 비교)

  • Kim, Yong-Joo Thomas;Lee, Ho-Sin David
    • International Journal of Highway Engineering
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    • v.12 no.1
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    • pp.79-86
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    • 2010
  • Cold in-place recycling (CIR) using emulsified asphalt or foamed asphalt has become a more common practice in rehabilitating the existing asphalt pavement due to its cost effectiveness and the conservation of paving materials. As CIR continues to evolve, the engineered emulsified asphalt was developed to improve the field performances such as coating, raveling, retained stability value and curing time. The main objective of this research is to compare the laboratory responses of the engineered emulsified asphalt (CIR-EE) mixtures against the foamed asphalt (CIR-foam) mixtures using the reclaimed asphalt pavement (RAP)materials collected from the CIR project on U.S. 20 Highway in Iowa. Based on the visual observation of laboratory specimens, the engineered emulsified asphalt coated the RAP materials better than the foamed asphalt because the foamed asphalt is to create a mastic mixture structure rather than coating RAP materials. Given the same compaction effort, CIR-EE specimens exhibited lesser density than CIR-foam specimens. Both Marshall stability and indirect tensile strength of CIR-EE specimens were about same as those of CIR-foam specimens. However, Marshall stability and indirect tensile strength of the vacuum-saturated wet specimens of CIR-EE mixtures were higher than those of CIR-foam mixtures. After four hours of curing in the room temperature, the CIR-EE specimens showed less raveling than the CIR-foam specimens. On the basis of test results, it can be concluded that the CIR-EE mixtures is less susceptible to moisture and more raveling resistant than CIR-foam mixtures.

A study on the operation characteristics of oversized exhaust port applicable to double-deck tunnel (복층터널에 적용 가능한 화재 연동형 대배기구 운영 특성 분석 연구)

  • Park, Jinouk;Yoo, Yongho;Kim, Yangkyun;Park, Byoungjik;Kim, Whiseong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.6
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    • pp.887-895
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    • 2019
  • Recently, the number of underground road development projects has been increasing to solve traffic problems in the national capital region and metropolitan areas with intensified overcrowding, and there has been a tendency to plan underground roads by applying a double-deck tunnel technology that has advantages in constructability and economical efficiency. The double-deck tunnel has a structure where one excavation section is divided into two parts and used as up and down lines, and is mainly used as a road for small vehicles only due to its low floor height. In addition, due to the small cross-sectional area, it has characteristics different from those of general road tunnels in terms of ventilation and disaster prevention. In this regard, this study proposed an operational plan that applies an oversized exhaust system, which is one of semi-transverse ventilation systems, to small cross-sectional tunnels like double-deck tunnel with low floor height, and a comparative analysis between smoke exhaust characteristics according to the fire occurrence locations and oversized exhaust systems was conducted using the Fire Dynamics Simulator (FDS). The results showed that unlike uniform exhaust, intensive smoke exhaust using the oversized exhaust port maximized the delay effect of smoke diffusion and limited the smoke within 50 m above and below the fire point.

Analysis on the Driving Safety and Investment Effect using Severity Model of Fatal Traffic Accidents (대형교통사고 심각도 모형에 의한 주행안전성 및 투자효과 분석)

  • Lim, Chang-Sik;Choi, Yang-Won
    • Journal of Korean Society of Transportation
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    • v.29 no.3
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    • pp.103-114
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    • 2011
  • In this study, we discuss a fatal accident severity model obtained from the analysis of 112 crash sites collected since 2000, and the resulting relationship between fatal accidents and roadway geometry design. From the 720 times computer simulations for improving driving safety, we then reached the following conclusions:. First, the result of cross and frequency-analyses on the car accident sites showed that 43.7% of the accidents occurred on the curved roads, 60.7% on the vertical curve section, 57.2% on the roadways with radius of curvature of 0 to 24m, 83.9% on the roads with superelevation of 0.1 to 2.0% and 49.1% on the one-way 2-lane roads; vehicle types involved are passenger vehicles (33.0%), trucks (20.5%) and buses (14.3%) in order of frequency. The results also show that the superelevation is the most influencing factor for the fatal accidents. Second, employing the Ordered Probit Model (OPM), we developed a severity model for fatal accidents being a function of on various road conditions so as to the damages can be predicted. The proposed model possibly assists the practitioners to predict dangerous roadway segments, and to take appropriate measures in advance. Third, computer simulation runs show that providing adequate superelevation on the segment where a fatal accident occurred could reduce similar fatal accidents by at least 85%. This result indicates that the regulations specified in the Rule for Road Structure and Facility Standard (description and guidelines) should be enhanced to include more specific requirement for providing the superelevation.

The Safety Evaluation of Expressway Geometries by Cross-sectional Analysis Techniques (횡단면 분석기법을 적용한 고속도로 기하구조 안전성 평가)

  • Seo, Im-Ki;Choi, Jong-Tae;Park, Je-Jin;Park, Shin-Hyoung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.2
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    • pp.417-426
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    • 2015
  • The representative design elements of the road geometric structure are longitudinal slope, horizontal curve radius, super elevation, and transition curve. According to the function of a road, the design standards of these elements is applied by diverse combinations of them. This study divided expressway into homogeneous segments based on longitudinal slope and horizontal curve radius. And then, data required for analysis were matched to each segment, and the safety performance function was built by using the established data. crash modification factors which can explain traffic accident exposure rate were calculated. When the threshold value of horizontal curve radius R=1,000 m was set to 1.0, the crash modification factors at R=300 m was calculated as 1.33, which means that the accident exposure rate is increased by 33%. When the threshold value of the longitudinal slope 0% was set to 1.0, the crash modification factors demonstrated that the accident exposure rate decreases on the upward slope and the accident exposure rate increases on the downward slope. The results of this study can be used as basic information in the design of expressway geometries during the improvement or the construction of expressways.

Morphological Interpretation of the Transformation Process of Urban Form in Gosan-Up (형태학적 개념을 활용한 조선시대 고산현의 도시형태 변천과정 해석)

  • Lee, Kyung-Chan;Kang, In-Ae
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.32 no.4
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    • pp.37-49
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    • 2014
  • This paper aims to interpret the transformation process of town plan of Gosan-up(高山), which was provincial administrative focus town in Josun dynasty, basing on morphological viewpoint. Morphological concepts, such as morphological frame, urban plan, kernel, colonization, route system, fixation line, fringe belt, plan unit & plan division, morphological period derived from the study of Conzen, M.R.G. and Caniggia, G. epidome district, break point, broken plot, urban fallow, privatization are adopted for the interpretation of urban form. Morphological period of Gosan can be divided in four ; formation of kernel & morphological structure, disintegration & redevelopment of the kernel, augmentative development of the kernel & formation of modern epidome district, outwards expanding of urbanized area, transition & reorganization of epidome district. Especially public leading projects such as construction of new regional connection road and public facilities such as myeon(township) office, agricultural cooperatives federation office, market, are main factors of morphological transformation of townplan. In the early stage, under the Japanese imperialism, construction of the new matrix route(Gosan-ro) through the kernel and followed planned routes gave way to disintegrating traditional areal plan unit and forming small block plan units in administrative facilities area. And linear plan units with commercial buildings were formed along the new matrix route and planned route adjacent to periodical market. In the latter stage, with development of public facilities, private sectors' large circulation institution and terminal outside the kernel with planned routes formed areal block based plan units with commercial and public buildings. And part of the spatial area with the linear plan unit were turned into urban fallow. With the transformation of town plan, new roads outside the kernel have substituted for traditional fixation line of waterway with road and topographical feature. Fringe belts were made successively along the new road and around the major intersections outside of existing urbanized area. Land use in fringe belts, constituting of outer locational tendency early on formation, was gradually replaced with commercial & business buildings.

Analysis on the Vegetation Structure of the Decomposed Granite Cut-slope - In case study on forest road of Gyeongsang-do and Jeolla-do - (화강암질 풍화토 절토비탈면의 식생구조 분석 - 경상도와 전라도 임도를 중심으로 -)

  • Song, Ho-Kyung;Park, Gwan-Soo;Lee, Joon-Woo;Lee, Mi-Jeong;Kim, Hyo-Jeong;Kwon, Oh-Won
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.1
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    • pp.59-67
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    • 2004
  • This study was carried out to select proper species for early stage replantation in granite forest roads cut-slope. From one to fourteen year elapsed forest roads in eight regional areas of Gyeongsang-do and Jeolla-do, sample plots were selected, and their vegetations and environmental factors were investigated. Soil organic matter, total nitrogen, soil moisture content, and bulk density in the granite weathering soils were below 0.4%, 0.03%, 12.4%, and above 1.2g/cm3, respectively. The result indicated that the soil was not good for plant growth. The environmental factors affecting distribution of species in the granite forest roads were the elapsed year, elevation, and cut-slope aspect. Invaded species with high frequency in the forest road cut-slope ordered Pinus densiflora, Lespedeza bicolor, Rubus crataegifolius, Alnus hirsuta, Youngia denticulata, Patrinia villosa, Artemisia princeps var. orientalis, Zanthoxylum schinifolium, and Dactylis glomerata. Herbs seeded in earth stage such as Dactylis glomerata, Eragrostis curvula, Festuca arundinacea, Lespedeza sp., and Amorpha fruticosa had changed into perennial herbs and shrubs such as Youngia denticulata, Patrinia villosa, Aster scaber, Patrinia scabiosaefolia, Melica onoei, Astilbe chinensis var. davidii, Chrysanthemum zawadskii var. latilobum, Pueraria thunbergiana, Stephanandra incisa, and Clematis apiifolia, and had changed into plants such as Artemisia princeps var. orientalis, Artemisia keiskeana, Miscanthus sinensis, Pinus densiflora, Rhododendron mucronulatum, Rubus crataegifolius, and Zanthoxylum schinifolium according to elapsed year of forest roads. Leguma such as Lespedeza sp., Pueraria thunbergiana, Amorpha fruticosa, etc., herbs such as Artemisia keiskeana, Artemisia princeps var. orientalis, Chrysanthemum zawadskii var. latilobum, Miscanthus sinensis, etc., and woody plants such as Pinus densiflora, Rubus crataegifolius, Rhododendron mucronulatum, etc., with foreign herbs were considered as proper species for replantation in granite forest road cut-slope.