• 농약과학회지
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• 제14권3호
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• pp.303-307
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• 2010

총설은 1996년 "농업생태계에 대한 잔류농약의 영향평가"라는 총설 이후 국내에서 발표된 토양 중에서의 농약의 동태에 관한 연구 보문을 요약 정리한 것이다. 내용은 농약의 지표면 유출, 농약의 토양 중 흡착 및 탈착, 농약의 토양 중 용탈, 농약의 토양 종 분해는 미생물에 의한 분해와 비생물학적 분해로 나누어 검토하였고, 농약의 토양 종에서의 행적 및 토양 중 잔류와 잔류 분석법 등으로 구분하여 정리하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.533-538
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• 2009

Ultimate lateral loaded pile capacity is influenced by soil conditions. Methods of calculating ultimate lateral loaded pile capacity in homogeneous soil were suggested by a lot of previous researchers.(Broms 1964, Petrasovits & Award 1972, Prasad & Chari 1999) There is only few homogeneous soil in actual condition, however, it could be not conviction that the methods from previous researchers are correct in multi-layered soil. In this study, ultimate lateral capacities were estimated from artificial multi-layered soils and were measured from lateral load test that were composed by various soil conditions. The influence of layered soil conditions were confirmed by comparing with two results.

• 한국지반공학회논문집
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• 제15권5호
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• pp.43-55
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• 1999

본 연구는 익산다짐풍화 화강토를 사용하여 여러가지 응력경로 시험을 실시하고 관측된 거동을 정확하게 예측할 수 있는 능력으로서 Yasufuku구성모델을 평가하였다. Yasufuku구성모델로 계산된 변형률은 측정치와 대부분 잘 일치하지만 약간의 차이를 나타내기도 하였다. 측정한 변형률과 계산한 변형률 사이에 가장 큰 차이를 보인곳은 증가하는 응력을 갖는 비례하중이 작용할 때 축변형률에 대하여 일어났다. Yasufuku 구성모델은 익산다짐풍화 화강토의 거동을 일정 구속압력하에서 축하중이 작용할 때와 p'-일정하중이 작용할 때 정확하게 추정할 수 있었다.

• 한국농공학회지
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• 제41권3호
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• pp.91-100
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• 1999

Tow constitutive models for weathered granite soil, Yasufuku's constitutive model with a single yield surface and Lade's constitutive model with two intersectiong yield surface compared in terms of their capabilities to accurately capture the observed behavior of compacted weathered grainite soil for various stress-paths. Both the single surface and the double surface models capture the experimentally observed behavior at a variety of stress-paths with good accuracy. The double surface model may model the observed compacted weathered granite soil behavior with better accuracy for proportational loading with increasing stress, but the single surface model may model dilatancy property with better accuracy for p-constant loading with increasing stress ratio.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.955-963
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• 2008

There are lots of tunnel intervals in the KTX II stage construction line for the linearity of railway line passing mountain region. In order to use the rocks from tunnel excavations, railway subgrades are constructed with crushed rock-soil mixtures. In this study, plain strain test using large scale box was conducted in order to analyze the characteristics of deformation behavior of railway subgrades composed of crushed rock-soil mixtures. The effects of variation of degree of saturation, stress level of applied loadings, and number of loading cycles on the resilient and permanent deformation behavior were analyzed. The results show that degree of saturation have a great effect on the deformation behavior of crushed rock-soil mixtures. The axial strain ranges between $0.1{\sim}0.8%$ with variation of degree of saturation, in assumption that deviatoric stress applied on the subgrade by high-speed train load is 55kPa.

• Coupled systems mechanics
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• 제7권1호
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• pp.27-42
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• 2018

Behavior of soil is usually described with continuum type of failure models such as Mohr-Coulomb or Drucker-Prager model. The main advantage of these models is in a relatively simple and efficient way of predicting the main tendencies and overall behavior of soil in failure analysis of interest for engineering practice. However, the main shortcoming of these models is that they are not able to capture post-peak behavior of soil nor the corresponding failure modes under extreme loading. In this paper we will significantly improve on this state-of-the-art. In particular, we propose the use of a discrete beam lattice model to provide a sharp prediction of inelastic response and failure mechanisms in coupled soil-foundation systems. In the discrete beam lattice model used in this paper, soil is meshed with one-dimensional Timoshenko beam finite elements with embedded strong discontinuities in axial and transverse direction capable of representing crack propagation in mode I and mode II. Mode I relates to crack opening, and mode II relates to crack sliding. To take into account material heterogeneities, we determine fracture limits for each Timoshenko beam with Gaussian random distribution. We compare the results obtained using the discrete beam lattice model against those obtained using the modified three-surface elasto-plastic cap model.

• Geomechanics and Engineering
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• 제16권3호
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• pp.309-320
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• 2018

In this paper, a numerical study using finite element method with considering soil-structure interaction was conducted to investigate the stress and deformation behavior of a sheet pile wall structure. In numerical model, one of the nonlinear elastic material constitutive models, Duncan-Chang E-v model, is used for describing soil behavior. The hard contact constitutive model is used for simulating the behavior of interface between the sheet pile wall and soil. The construction process of excavation and backfill is simulated by the way of step loading. We also compare the present numerical method with the in-situ test results for verifying the numerical methods. The numerical analysis showed that the soil excavation in the lock chamber has a huge effect on the wall deflection and stress, pile deflection, and anchor force. With the increase of distance between anchored bars, the maximum wall deflection and anchor force increase, while the maximum wall stress decreases. At a low elevation of anchored bar, the maximum wall bending moment decreases, but the maximum wall deflection, pile deflection, and anchor force both increase. The construction procedure with first excavation and then backfill is quite favorable for decreasing pile deflection, wall deflection and stress, and anchor forces.

• 한국지반환경공학회 논문집
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• 제5권1호
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• pp.65-73
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• 2004

파형강관의 해석은 2차원 프레임 해석이나 압축링 모델에 의존하고 있다. 이는 흙-구조물 합성구조계의 거동을 고려하지 않은 해석이다. 파형강관 구조물은 토피고와 지간에 따라 하중저항시스템이 변화한다. 따라서, 흙-구조물 합성구조계의 작용을 고려한 유한요소해석을 통해 파형강관의 거동특성을 확인하였다. 적정토피고 이상 성토하면 파형강관은 연성관의 토압분포에 따른 거동과 유사하며, 차량하중의 영향은 적정토피고 이상 성토할수록 감소하였다. 그러나, 적정토피고 이하로 성토할 경우, 연직토압이 감소하고 파형강관 측면의 수동토압도 감소하여 완전한 연성관 거동을 나타내지 못했고, 성토 높이가 적정토피고 이하로 작아질수록 차량하중이 단면력에 미치는 영향이 커져, 파형강관 구조물의 거동을 지배하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 기초기술학술발표회
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• pp.77-89
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• 2002

To analyze a bearing capacity for pile groups, a number of model tests have been done and theoretical methods studied. In the case of design of group pile bearing capacity is calculated with only pile capacity. But uncertainty of bearing capacity and behavior of foundation cap(raft) leads to conservative design ignoring bearing effects of foundation cap. In the case of considering bearing capacity of foundation cap, the simple sum of bearing capacity of foundation cap and pile groups cannot be the bearing capacity of total foundation system. Since cap-pile-soil interaction affects the behavior of pile groups. Thus, understanding cap-pile-soil interaction is very important in optimal design. In this paper, the piled raft behavior is studied through model tests of 2$\times$2, 2$\times$3, 3$\times$3 pile group. Changes of behavior of pile group foundation by touching effects of foundation cap with soil are studied. Also changes of spacing between piles. Foundation cap is made of rigid steel plate and piles are made steel pipes. From this model tests, the changes of behavior changes of pile groups by touching effects of foundation cap with soil are studied.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1014-1023
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• 2006

Soil nailing is a reinforcement method used for stabilizing excavated wall or slope. Due to its many advantages such as ease of construction and economical efficiency, use of soil nailing is increased. However, the soil nail can't trespass on the neighbor private land, which pays rent for use. For this reason, removable soil nailing system was developed. However, the removal rate of this system is just about $50\sim70%$. To solve this, the Fiber Reinforced Polymer (FRP) soil nailing system, which does not need to be removed and allows for the trespass on the private land, is developed. In this paper, through theoretical and experimental studies in laboratory and field, we evaluate the stability and behavior characteristics of the FRP nail system. Besides, numerical analyses using FLAC2D were performed for various soil conditions, where the simulations for pullout tests were carried out. As a result, compared with the conventional removable soil nailing system, the FRP soil nailing systems show similar behavior characteristics.