• 한국지반환경공학회 논문집
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• 제7권3호
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• pp.69-76
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• 2006

본 연구는 모래지반에서 공동위에 위치한 연속기초의 지지력거동을 연구하기 위하여 강사법으로 조성된 모래지반에서 모형실험을 수행하였다. 모형실험결과와 이론식을 비교하여 지하공동이 연속기초의 지지력에 영향을 미치는 한계범위를 도출하였다. 한계범위의 크기는 기초의 형상, 지반특성, 공동크기, 공동형상 등 여러 가지 인자에 의존한다. 지하공동의 깊이가 편심거리보다 극한지지력에 더 큰 영향을 주는 것으로 나타났다. 또한 연속기초에 미치는 지하공동의 영향은 편심거리에 따른 지지력 감소현상 뿐만 아니라 연속기초의 부등침하 현상에도 큰 영향을 줄 것으로 판단되었다.

• 한국약용작물학회지
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• 제22권4호
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• pp.301-305
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• 2014

This study was carried out to investigate the vegetation and habitat environment of Sageretia thea which is distributed in Jeju island, Korea. Sageretia thea were mainly distributed to the west area in Jeju island. Soil pH and EC of Sageretia thea habitat were 5.8 and $0.34dS{\cdot}m^{-1}$. The contents of organic matter, available phosphate, exchangeable potassium, exchangeable sodium, exchangeable magnesium and exchangeable calcium were 15.27%, $13.6mgkg^{-1}$, $0.27cmol_+kg^{-1}$, $1.3cmol_+kg^{-1}$, $1.7cmol_+kg^{-1}$, $4.9cmol_+kg^{-1}$, respectively. Thirty one taxa including 25 families, 31 genus, 27 species and 4 varieties were identified surrounding Sageretia thea habitat. Specific plant species were 1 taxon in III grade, 1 taxon in I grade and 3 taxa in I grade.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.749-758
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• 2010

Embankment Slope (or Fill Slope) is defined as artificial slope formed by the filling of soil or rocks on the original ground. Recently a lot of embankment failures and collapse has occurred due to the increase of torrential rainfall and typhoons. Embankment collapse has lead to a great loss of lives and property therefore there is a need to establish a systematic embankment slope management system that will handle the maintenance and repair of risky embankment slopes. The objective of this study is to establish an "Embankment Slope Management Method" for embankment slopes located along national highways all over Korea. The method for field investigation of embankment slopes was recommended and the system for investment priority determination was also developed. The factors that lead to the collapse of embankment slopes caused by natural calamities were also determined through the initial survey of embankment slopes located along river fronts and mountainous areas.

• 한국지반공학회지:지반
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• 제13권3호
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• pp.5-20
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• 1997

본 연구에서는 유한변형률 이론에 근거하여 3차원 압밀 지배 방정식을 유도하였다. 이 방정식은 비교적 압밀층의 두께가 두꺼운 경우, 비선형 물성치, 공극비에 따른 비선형 투수계수를 갖는 지반에 적합하다. 기존의 유한차분 수치해석 기법(FTCS)은 지배 방정식이 비선형 이며 복잡한 경우 안정된 해를 얻을 수 없기 때문에 본 연구에서는 특수 유한 차분 기법을 도입하였다. 이 수치해석 기법을 지배 방정식에 적용하면 시간에 따른 압밀량을 예측할 수 있다. 본 해석기법에 의해 구해진 값들을 윅드레인을 설치한 여러 가지 고압축성 토질에서의 실험 결과와 비교한 결과, 최종 압밀량과 시간에 따른 압말량이 잘 일치하고 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.174-187
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• 2005

Recently, because of environment, cost, supply and demand factors, though applying sea-sand as horizontal drains is getting difficult that usage of Gravel has been growing in large size of construction sites, Study on engineering properties and behavior characteristics of Gravel stratum is not thoroughgoing enough. We have applied Gravel Mat as the horizontal drains in O O construction site. We also conducted several field tests such as Material property test, Geosynthetics damage test with Repeated load, Discharge capacity test performed by inflow of upper soil and In-situ PBD Penetration test to review the application of Gravel Mat. Test results show that Gravel Mat is not only advantageous in Trafficability and Water drainage by Consolidation due to its great Internal friction angle and Permeability, but also easy to penetrate with Mandrel and has great discharge capacity and guarantee of the stability against geosynthetics damage at the same time. With these benefits Gravel Mat shows great application in fields.

• 한국환경복원기술학회지
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• 제19권1호
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• pp.155-170
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• 2016

This study established the definition of invasive disturbance species for a sustainable management and biodiversity, and derived the influence factors caused by the species. To define the species, the paper reviewed similar words such as alien species and invasive species, using standard definitions. Also reviewed the results of recent research on the factors of the species. The paper defined the invasive disturbance species as an species whose establishment and spread threaten ecosystems, habitats or species with economic or environmental harm including native and non-native. Through the reviews, The factors were classified as geographic (altitude, slope, and soil, etc.), climate (temperature, precipitation, climate change, etc.) and, anthropogenic (land use, population, road, and human activity, etc.), and species & vegetation structure (species property, local-species richness, and canopy, etc.). Especially, human activity such as urbanization and highways may be associated with both higher disturbance and higher propagule pressure. In the further study, it is required development of mitigation strategies and vegetation structure model against invasive disturbance species in urban forest based on this study.

• 한국미생물·생명공학회지
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• 제30권4호
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• pp.332-338
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• 2002

토양으로부터 세포외로 $\alpha$-galactosidase를 분비 생산하는 방선균 YB-4가 분리되었으며, 분리균의 배양ㆍ형태ㆍ생리적 특성을 조사한 결과 Streptomyces 속 균주로 확인되었다. 분리균의 배양상등액으로부터 부분정제된 $\alpha$-galactosidase를 조효소액으로 사용하였을 때 para-nitrophenyl-$\alpha$-D-galacto-pyranoside는 pH 6.0과 6$0^{\circ}C$의 반응조건에서 가장 잘 분해되었으며, 조효소액을 pH 4.0에서 pH 10.0범위에서 1시간 이상 방치한 후에도 약 90% 이상의 $\alpha$-galactosidase 활성을 유지하였다. 또한 분리균이 생산하는 $\alpha$-galactosidase는 melibiose, raffinose와 stachyose와 같은 저당류를 가수분해 할 수 있으며 분해산물로 galactose를 방출하는 것으로 보아 $\alpha$-1,6 결합을 분해한 것으로 확인되었다.

• 한국지반공학회지:지반
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• 제14권2호
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• pp.79-92
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• 1998

실내모형실험으로 전기비저항치와 오염된 흙의 물리적 성질과의 상관관계를 규명하기 위해서 요소분석을 수행하였다. 세가지의 모래질 구에 산업폐기물매립지의 침출수를 첨가하여 모형실험에 이용했다. 혼합토의 전기비저항치는 비저항콘을 모사한 프로브를 제작하여 측정했다. 실내모형실험에서는 흙의 함수비, 간극비. 단위중량, 함수비 및 침출수의 농도를 변화시키면서 혼합토의 전기비 저항치를 계측했다. 실험결과는 흙의 종류 및 단위중량보다는 흙의 함수비, 간극수의 전도성이 전기비저항치에 큰 영향를 미치고 있음을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.276-285
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• 2006

Application of anchored or strutted wall system for the earth retention of excavation works in a populated urban area or a poor soil deposit can be limited due to various restrictions. Since the strut becomes longer in a wide excavation site, the stability of an earth retaining wall is decreased, the wall deformation is increased, and the ground settlement is also increased due to an increased buckling or bending deformation of struts. Especially, in a populated urban area, the installation of anchors can be problematic due to the property line of adjacent structures or facilities. Thus, a new concept of earth retaining system like Self-Supported diaphragm Wall can solve several problems expected to occur during excavation in the urban area. In this study, Numerical analyses of counterfort diaphragm wall was introduced and the monitored data from the site was compared with the original results of numerical analyses. Also, in the case of the deep excavation applied the counterfort diaphragm wall, numerical analyses was performed to predict the wall deformation and the reinforcement to reduce the wall deformation was suggested.

• Computational Structural Engineering : An International Journal
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• 제1권1호
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• pp.31-38
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• 2001

In the case of the non-proportionally damped system such as the soil-structure interaction system, the structural control system and composite structures, the eigenproblem with the damping matrix should be necessarily performed to obtain the exact dynamic response. However, most of the eigenvalue analysis methods such as the subspace iteration method and the Lanczos method may miss some eigenvalues in the required ones. Therefore, the eigenvalue analysis method must include a technique to check the missed eigenvalues to become the practical tools. In the case of the undamped or proportionally damped system the missed eigenvalues can easily be checked by using the well-known Sturm sequence property, while in the case of the non-proportionally damped system a checking technique has not been developed yet. In this paper, a technique of checking the missed eigenvalues for the eigenproblem with the damping matrix is proposed by applying the argument principle. To verify the effectiveness of the proposed method, two numerical examples are considered.