• 한국지반공학회지:지반
• /
• 제12권3호
• /
• pp.5-16
• /
• 1996

실리카질 모래에 대한 많은 시험결과로부터 삼축압축시첩과 평면변형시험간의 강도관계를 밀도와 파괴시 유효평균주응력의 함수로 표현하였다. 또한 파괴시 평균주응력과 축차응력간의 응력비가 내부마찰각의 함수로 잘 규정되었으며 그 비는 내부마찰각의 증가에 따라 감소하였다. 또한 중간주응력을 최대주응력과 최소주응력으로써 표현하였으며 이론적인 파괴면의 각도와 평면변형시험에서 관찰된 파괴면의 각도가 비교적 잘 일치함이 확인되었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2006년도 추계 학술발표회
• /
• pp.256-267
• /
• 2006

After heavy rainfall, It was occurred massive plane failure along bedding plane of shale in the center of rock slope. It was observed filling material and trace of underground water leakage around of the slope. We tried to find the cause for slope failure, and the result of examination showed that primary factors of the failure were low shear strength of clay filling material and water pressure farmed within tension crack existed in the top of the slope. In this research, in order to examine the features of shear strength of filled rock joint, shear test of filled rock joint was conducted using of artificial filling material such as sand and clay. Also we made an investigation into the characteristics of shear strength with different thickness of filling materials.

• Computers and Concrete
• /
• 제8권6호
• /
• pp.735-755
• /
• 2011

The capability of a multi-directional fixed smeared crack constitutive model to simulate the flexural/punching failure modes of fiber reinforced concrete (FRC) laminar structures is discussed. The constitutive model is implemented in a computer program based on the finite element method, where the FRC laminar structures were simulated according to the Reissner-Mindlin shell theory. The shell is discretized into layers for the simulation of the membrane, bending and out-of-plane shear nonlinear behavior. A stress-strain softening diagram is proposed to reproduce, after crack initiation, the evolution of the normal crack component. The in-plane shear crack component is obtained using the concept of shear retention factor, defined by a crack-strain dependent law. To capture the punching failure mode, a softening diagram is proposed to simulate the decrease of the out-of-plane shear stress components with the increase of the corresponding shear strain components, after crack initiation. With this relatively simple approach, accurate predictions of the behavior of FRC structures failing in bending and in shear can be obtained. To assess the predictive performance of the model, a punching experimental test of a module of a façade panel fabricated with steel fiber reinforced self-compacting concrete is numerically simulated. The influence of some parameters defining the softening diagrams is discussed.

• 한국강구조학회 논문집
• /
• 제24권2호
• /
• pp.137-147
• /
• 2012

본 연구는 L형, I형 실험체에 강판 콘크리트 구조와 철근콘크리트 구조를 적용하여 이질접합부를 만들고, 실험체에 반복하중을 파괴 시 까지 가력하여 면외 휨 내력 및 면내 전단 내력을 평가하고 구조특성을 검토하기 위해서 실험연구를 수행하였다.본 연구에서 면외 휨 성능실험은 접합부에서 정착부 수직철근이 인발되면서 파괴되었고, 면내 전단성능실험은 기초부에서의 휨 균열이 발생하여 파괴되었으며, 이론식과의 비교결과 최대 내력이 실험값/이론값의 결과가 면외 휨성능실험은 96%, 면내 전단성능실험은 82%의 값을 나타내었다.

• Earthquakes and Structures
• /
• 제22권4호
• /
• pp.355-372
• /
• 2022

The study is part of an experimental program on full-scale Un-Reinforced Masonry (URM) wall panels strengthened with Textile reinforced mortars (TRM). Eight brick walls (two with and five without central opening), were tested under the diagonal tension (shear) test method in order to investigate the strengthening system effectiveness on the in-plane behaviour of the walls. All the URM panels consist of the innovative components, named "Orthoblock K300 bricks" with vertical holes and a thin layer mortar. Both of them have great capacity and easy application and can be constructed much more rapidly than the traditional bricks and mortars, increasing productivity, as well as the compressive strength of the masonry walls. Several parameters pertaining to the in-plane shear behaviour of the retrofitted panels were investigated, including shear capacity, failure modes, the number of layers of the external TRM jacket, and the existence of the central opening of the wall. For both the control and retrofitted panels, the experimental shear capacity and failure mode were compared with the predictions of existing prediction models (ACI 2013, TA 2000, Triantafillou 1998, Triantafillou 2016, CNR 2018, CNR 2013, Eurocode 6, Eurocode 8, Thomoglou et al. 2020). The experimental work allowed an evaluation of the shear performance in the case of the bidirectional textile (TRM) system applied on the URM walls. The results have shown that some analytical models present a better accuracy in predicting the shear resistance of all the strengthened masonry walls with TRM systems which can be used in design guidelines for reliable predictions.

• 한국구조물진단유지관리공학회 논문집
• /
• 제14권4호
• /
• pp.94-101
• /
• 2010

최근 건설공사의 공기단축을 위하여 프리캐스트 콘크리트(Precast Concrete)에 대한 관심이 점차 증가하는 추세이다. 본 연구에서는 프리캐스트 콘크리트 중 내부에 중공을 설치하여 중량을 감소시킨 할로우코어 슬래브 간의 접합부 전단성능 평가에 대한 실험적 연구를 수행하였다. 실험의 주요 변수는 할로우코어 슬래브 상부의 토핑콘크리트의 두께와 와이어메쉬의 배근유무이며, 총 8개의 슬래브간 접합부 실험체 중 4개의 면내전단실험과 4개의 면외방향 전단실험을 수행하였다. 실험의 결과는 균열하중, 파괴하중, 파괴양상, 강성 및 연성도의 측면에서 분석하였으며, 실험결과를 설계하중과 비교 검토함으로써 최적의 디테일을 개발할 수 있는 실험적 근거를 제공하도록 하였다. 실험결과, 슬래브 간 접합부에 무수축 모르타르를 타설한 경우에는 토핑두께 30mm의 보통 콘크리트를 사용한 것과 유사한 구조성능을 발현할 수 있는 것으로 평가되었으며, 와이어메쉬의 보강효과는 내력 및 강성보다는 연성의 증가에 크게 기여하는 것으로 나타났다. 또한, 토핑콘크리트의 두께에 따른 설계하중과의 비교를 통하여 적절한 디테일 설계를 할 수 있는 기초적 자료를 제공하였다.

• 터널과지하공간
• /
• 제16권5호
• /
• pp.368-376
• /
• 2006

셰일층으로 구성된 암반사면에서 층리면을 따라 대규모 평면파괴가 사면 중앙부에서 발생하였다. 현장조사시 파괴사면 주변은 지하수 누수 흔적과 점토층의 충전물이 존재하였으며, 파괴원인을 검토한 결과 층리면을 따라 형성된 점토 충전물의 낮은 전단강도와 강우시 인장균열내 형성된 수압에 의해 붕괴가 발생한 것으로 나타났다. 그리고 충전된 절리면의 전단강도 특성을 규명하기 위해서 모래, 점토의 인위적인 충전물을 이용하여 충전재 두께비에 따른 전단강도 특성을 고찰하였다.

• 한국지반공학회논문집
• /
• 제32권3호
• /
• pp.49-60
• /
• 2016

일반적으로 흙의 파괴는 전단 변형이 집중되는 영역인 전단면의 형성과 발달에 의해 발생한다. 정규압밀 점성토의 파괴거동을 확인하기 위해 시료 내부의 변형거동 분포에 대해 평가가 필요하다. 본 연구에선 재성형된 카올리나이트 시료에 대해 평면변형률 시험을 수행하였으며, 전단 과정에서 일정 변형률 간격에서 디지털 이미지 해석을 수행하였다. 시험 결과로 도출된 응력-변형률 결과를 통해 4개의 단계를 결정하여 시료의 변형거동과 전단면 특성을 평가하였다.

• Geomechanics and Engineering
• /
• 제13권3호
• /
• pp.431-446
• /
• 2017

Rock bridges in rock masses would increase the bearing capacity of Non-persistent discontinuities. In this paper the effect of ratio of rock bridge surface to joint surface, rock bridge shape and normal load on failure behaviour of intermittent rock joint were investigated. A total of 42 various models with dimensions of $15cm{\times}15cm{\times}15cm$ of plaster specimens were fabricated simulating the open joints possessing rock bridge. The introduced rock bridges have various continuities in shear surface. The area of the rock bridge was $45cm^2$ and $90cm^2$ out of the total fixed area of $225cm^2$ respectively. The fabricated specimens were subjected to shear tests under normal loads of 0.5 MPa, 2 MPa and 4 MPa in order to investigate the shear mechanism of rock bridge. The results indicated that the failure pattern and the failure mechanism were affected by two parameters; i.e., the ratio of joint surface to rock bridge surface and normal load. So that increasing in joint area in front of the rock bridge changes the shear failure mode to tensile failure mode. Also the tensile failure change to shear failure by increasing the normal load.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회
• /
• pp.743-748
• /
• 2010

The stability forecasting of rock slope is more difficult than soil slope because catching the sign of failure in monitoring is not easy and deformation of the rock is small in failure process. But in the rock slope, there is small deformation like crack propagation in rock itself and it accumulates gradually in failure process. If it is possible to detect the small change in the rock slope, we can know the failure time exactly. Because the individual signal is gathered in the acoustic emission monitoring, it is possible to monitoring the slope if many sound signal is accumulated. Detection test of acoustic emission was performed. Uniaxial, two types of bending test, and two plane shear test were done with various cement paste sample. Wave propagation velocity of uniaxial test sample was increased with curing time. Wave Analysis give us the result that there is a AE sign signal before the failure, the AE count is suddenly increased. And frequency level 125kHz before failure is changed to level 200-250kHz after failure. In two plane shear test we can catch the AE signal and can know the failure type from wave shape. Monitoring test site is tunnel slope in Hongcheon but special signal is not collected.