• 제목/요약/키워드: Environmental capacity

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현장시험을 통한 수평배수재로서의 풍쇄 슬래그의 적용성에 관한 연구 (Application of Precious Slag Ball for horizontal drain material by field experimental test)

  • 신은철;이운현;김수완;유정훈
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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    • pp.449-456
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    • 2009
  • As soft grounds have complex engineering properties that the load bearing capacity is low and high compressibility, it needs to solve this problems prior to structures are constructed by the method of improvement of soft ground. Generally, the sand mat is used to as a horizontal drain material and loading base for soft ground improvement work. However, as the natural environment can be damaged by sand pickings of large quantity and the volume which is enormous and an amount of demanded sand is increased, it is state of short in supply. This paper presents the result of field experimental test to use Precious Slag Ball to solve these issues instead of sand mat as the replacing material. This study evaluated the performance of Precious Slag Ball as a sand mat in terms of discharge capacity, settlement, and settlement through the K-Embank program.

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유한요소해석에 의한 석회암 공동지반의 변형특성에 관한 연구 (A Study of the Deformation Characteristics in Limestone Cavity Area by Finite Element Method)

  • 천병식;박형준
    • 한국지반환경공학회 논문집
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    • 제6권1호
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    • pp.63-72
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    • 2005
  • 석회암은 지질학적, 공학적 특성상 견고하여 지지층으로 충분한 역할을 할 수 있으나, 지반 내의 불안정한 요소인 용해성 공동과 연약점토층이 협재된 파쇄대가 있을 경우 구조물의 지지력과 침하에 대한 장기적인 안정성 검토와 대책이 필요하다. 따라서 본 논문에서는 석회암 공동의 안정성 검토를 위해 허용지지력과 변위특성에 대해 연구하였다. 허용지지력은 Bell과 Bowles의 결과치가 비슷하지만, Hoek-Brown의 제안식에 의한 값은 다른 제안식들에 비해 상당히 크게 산정되었다. 풍화암질 석회암인 경우 석회공동의 크기와 심도에 따라 안정성 여부가 변화하였지만, 연암 및 경암의 경우 최대 변위량이 허용치 이내에 있어 석회공동이 기초의 안정에 큰 영향을 미치지 않았다.

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Investigation on structural behaviour of composite cold-formed steel and reinforced concrete flooring systems

  • Omar A., Shamayleh;Harry, Far
    • Steel and Composite Structures
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    • 제45권6호
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    • pp.895-905
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    • 2022
  • Composite flooring systems consisting of cold-formed steel joists and reinforced concrete slabs offer an efficient, lightweight solution. However, utilisation of composite action to achieve enhanced strength and economical design has been limited. In this study, finite element modelling was utilised to create a three-dimensional model which was then validated against experimental results for a composite flooring system consisting of cold-formed steel joists, reinforced concrete slab and steel bolt shear connectors. This validated numerical model was then utilised to perform parametric studies on the performance of the structural system. The results from the parametric study demonstrate that increased thickness of the concrete slab and increased thickness of the cold formed steel beam resulted in higher moment capacity and stiffness of the composite flooring system. In addition, reducing the spacing of bolts and spacing of the cold formed steel beams both resulted in enhanced load capacity of the composite system. Increasing the concrete grade was also found to increase the moment capacity of the composite flooring system. Overall, the results show that an efficient, lightweight composite flooring system can be achieved and optimised by selecting suitable concrete slab thickness, cold formed beam thickness, bolt spacing, cold formed beam spacing and concrete grade.

원심모형 실험과 수치해석을 이용한 과압밀 지반에서의 말뚝지지 전면기초의 지지력 평가 (Evaluation of Bearing Capacity of Piled Raft Foundation on OC Clay Using Centrifuge and Numerical Modeling)

  • 박진오;추연욱;김동수
    • 한국지반공학회논문집
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    • 제25권7호
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    • pp.23-33
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    • 2009
  • 본 연구에서는 말뚝지지 전면기초의 거동을 원심모형시험과 수치해석기법을 이용하여 연구하였다. 단말뚝, 기초판, 군말뚝 및 말뚝지지 전면기초의 극한지지력 비교를 통하여 말뚝지지 전면기초의 지지력을 평가하였고, 말뚝과 기초판에 전달되는 하중 분담율을 분석하여 말뚝지지 전면기초의 극한지지력을 산정할 수 있는 경험적 상관계수를 획득하였다. 또한, 원심모형시험과 동일말뚝조건을 대상으로 수치 시뮬레이션을 수행하여 원심모형시험 결과를 검증하고 말뚝지지 전면기초의 지지력을 위한 상관계수를 평가하였다.

Geocell을 활용한 도로포장 공법별 지지력 비교 분석 (Comparative Analysis of Bearing Capacity by Road Pavement Method Using Geocell)

  • 이수형;진현우
    • 한국지반환경공학회 논문집
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    • 제24권12호
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    • pp.19-29
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    • 2023
  • 도로의 주된 문제는 표층에서부터 작용하는 하중으로 인해 시간이 지남에 따라 균열 및 침하가 발생한다. 이러한 문제를 해결하기 위한 방법 중 하나로 지오셀(Geocell)을 사용하는 것이 있는데, 지오셀은 침식 방지, 평지 및 급경사지에서의 지반 안정화, 하중지지 및 지반 보전을 위한 구조적 보강을 위해 사용될 수 있다. 본 연구에서는 국내외 지오셀을 활용한 도로포장 적용 사례를 분석하고, 현장 시험과 LFWD(Light Falling Weight Deflectometer) 장비를 이용한 지오셀이 포함된 도로 포장 공법에 따른 지지력을 분석하고 기존도로포장 공법과 지지력을 비교·분석 하고자 한다.

Study on Thermal Load Capacity of Transmission Line Based on IEEE Standard

  • Song, Fan;Wang, Yanling;Zhao, Lei;Qin, Kun;Liang, Likai;Yin, Zhijun;Tao, Weihua
    • Journal of Information Processing Systems
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    • 제15권3호
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    • pp.464-477
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    • 2019
  • With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

가축분뇨의 자원화 용량 평가에 관한 연구 (A Study on Recycling Capacity Assessment of Livestock Manure)

  • 안태웅;최이송;오종민
    • 환경영향평가
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    • 제17권5호
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    • pp.311-320
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    • 2008
  • Reusing livestock manure have various advantages in securing soil organic resources, and since the costs needed for converting them into liquefied fertilizers are relatively moderate compared to normal treatment, such methods are necessary. In this study, the Recycling Capacity Assessment of Gyeonggi-do was carried out by comparing between the fertilizer demands for specific crops based on the cultivation areas and the amount of fertilizer resources that are generated from livestock manure. From this assessment, the possibility of obtaining resources by converting livestock manure into fertilizers were evaluated. The amount generated of Livestock Manure in Gyeonggi-do were evaluated by applying the emission units to the number of livestock manure. And from the amount generated of Livestock Manure, the amount of fertilizer produced from Livestock Manure were calculated by using the fertilizer a component rate. When considering the amount of fertilizer produced from Livestock Manure based on the type of livestock, N 6,626 ton/year, $P_2O_5$ 1,824 ton/year, $K_2O$ 4,480 ton/year were produced from milk cow manure, while N 5,247 ton/year, $P_2O_5$ 2,772 ton/year, $K_2O$ 2,879 ton/year, were produced from beef cattle manure. N 14,924 ton/year, $P_2O_5$ 7,205 ton/year, $K_2O$ 6,750 ton/year were produced from pigs and N 12,651 ton/year, $P_2O_5$ 4,458 ton/year, $K_2O$ 5,542 ton/year were produced by chickens. So the total amount of fertilizers that can be obtained from livestock manure were 3,668 ton/year Nitrogen, 16,259 ton/year phosphate and 19,651 ton/year kalium. And the total fertilizer demands in Gyeonggi-do were Nitrogen 27,200 ton/year, Phosphate 8,853 ton/year, and kalium 13,211 ton/year respectively. Nitrogen which had higher demands than production quantities were considered as limitation factors in crop growth. So the Recycling Capacity Assessment was carried out mainly based on Nitrogen. Since the Nitrogen quantities that can be provided by recycling livestock manure were 3,532 ton/year lesser than the Nitrogen demands, it is estimated that it would be desirable to convert livestock manure into resources. But in order to properly convert the entire livestock manure into organic resources, the seasonal situation that effects the nitrogen demands of crops along with the regional effects due to the industrial structures should be seriously analyzed. In addition, a system that can effectively produce and manage fertilizer should be established.

자연광석을 이용한 염소계 지방족 탄화수소 혼합물 변환 특성 (Transformation Characteristics of Chlorinated Aliphatic Hydrocarbon (CAH) Mixtures by Natural Ores)

  • 손봉한;김남희;홍광표;윤준기;이채영;김영;권수열
    • 한국물환경학회지
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    • 제23권5호
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    • pp.712-722
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    • 2007
  • This study screened three natural ores (iron, mangenase, and zinc), two types of slags, and two elemental metals (elemental iron and zinc) to evaluate transformation characteristics of CAH mixtures [e.g. Carbontetrachloride (CT), 1,1,1-Trichloroethane (1,1,1-TCA), and Perchloroethene (PCE)]. To select an effective metal medium to treat the CAH mixtures, we measured transformation capacities (CAH mass ultimately transformed/mass of metal added) and the degree of dechlorination. We also considered economical efficiency of the metal media by comparing the value, CAH mass ultimately transformed divided by the price of metal medium added. A simplified mathematical model adapting CAH transformation capacity, first-order transformation kinetics, and available mass of metal transforming CAH was developed and used for estimating CAH transformation rate coefficient and longevity of the metal medium. CAH transformation capacity for elemental iron and elemental zinc were 4258~7129 and $4215{\sim}6330{\mu}g\;CAH\;transformed/g$ metal added, respectively, which are a factor of 80~200 higher than slags and natural ores. They also showed a factor of 1.1 to 2.2 greater degree of dechlorination than the others. Among natural ores and slags, Zinc ore showed the highest transformation capacity, $47{\sim}53{\mu}g\;CAH\;transformed/g$ metal added. Although zinc ore have smaller transformation capacity than elemental metals, economical efficiency of zinc ore is a factor of 10~20 greater than elemental metals tested. Consequently, zinc ore would be more economical medium than the others tested in this study. We estimated the pseudo first-order transformation rate of zinc ore was in the order of CT > 1,1,1-TCA > PCE.

부산광역시의 해양환경관리 자치역량 분석 (Self-Governing Capacity of Ocean Environmental Management of Busan Metropolitan City)

  • 최성두;강은숙;김상구;박상희;송영채;이경은
    • 한국항해항만학회지
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    • 제32권6호
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    • pp.515-519
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    • 2008
  • 본 연구는 해양특별시의 설치를 최고의 당면과제로 추진하고 있는 부산광역시의 해양환경관리 자치역량를 분석한 논문이며, 연구방법으로는 Lester(1990)가 주장하는 환경자치의 역량분석기법을 사용하였다. Lester(1990)의 연구방법에 따라 본 연구에서는 분석의 변수로서 자치단체장의 의지와 물적 토대 통을 사용하였다. 먼저 자치단체장의 의지를 분석한 결과, 부산광역시장과 관계공무원의 해양과 환경에 대한 관심도는 우리나라 제1의 해양토시라는 특수성에 비추어 비교적 낫은 수준이었다. 그리고 물적 토대를 측정하기 위하여 담당공무원수와 해양환경예산규모를 다른 7대 광역시와 비교한 결과, 다른 대도시에 비하여 높지 않은 수준이었다. 결론적으로 부산광역시의 해양환경관리 자치역량 수준은 퇴보형이거나 아니면 지체형에 속한다고 판단할 수 있었다.

PHC-W 흙막이 벽체를 이용한 건축물 지하증설벽체에서 PHC-W말뚝의 선단지지력 산정에 관한 연구 (A Study on Estimation of End Bearing Capacity of a PHC-W Pile in Building Underground Additional Wall Using the PHC-W Earth Retaining Wall)

  • 김채민;윤대희;이창욱;;김성수;최용규
    • 한국지반공학회논문집
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    • 제35권3호
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    • pp.5-16
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    • 2019
  • 최근 도시 인구의 밀집으로 대형구조물의 건설이 증가하고 있으며 이와 더불어 대형구조물의 기초도 발전하고 있다. 2000년대 말에 일본의 기술을 도입하여 PHC말뚝은 많은 구조물에 사용되고 있다. 최근 PHC말뚝의 장점을 이용하여 흙막이 벽체로의 사용에 대한 연구가 많이 진행되고 있으며, 이 연구에서는 PHC-W 흙막이 벽체를 이용한 건축물 지하증설벽체에서 PHC-W말뚝을 주열식으로 시공하여 연직 압축정재하시험을 실시하였으며, 하중전이 측정을 통하여 PHC-W말뚝의 선단지지력을 산정하였다. 풍화암에 근입된 PHC-W말뚝의 지지력은 기존 PHC말뚝의 지지력과는 차이를 보였으므로, 주열식으로 시공된 PHC-W말뚝의 선단지지력 산정식을 제안하였다. 풍화암에 근입된 PHC-W말뚝의 단위극한선단지지력 산정식으로 주열식 군PHC-W말뚝과 단일PHC-W말뚝에서 각각 $q_b=6.8N_b$$q_b=13.3N_b$로 제안할 수 있었다.