• Title/Summary/Keyword: 평면변형률시험

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A Newly-developed Plane Strain Testing Device and Its Applicability (새로운 평면변형률 시험장비의 개발과 적용성 검증)

  • Kim Chang-Youb;Lee Young-Sun;Chung Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.22 no.1
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    • pp.5-14
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    • 2006
  • A simple and useful plane strain testing device was newly developed and its mechanical features were presented in this paper. The new testing device was designed to be capable of testing various stress paths expected under plane strain condition with only the conventional triaxial loading system. The applicability of the new testing device was systematically checked both by theoretical evaluation and by experiments. As a result, it was found that the new testing device has much wider range of application than the conventional plane strain testing devices.

Restrained Effect of End Plate on Plane Strain Test Evaluated by Digital Image Correlation Method (디지털 이미지 코릴레이션 기법으로 평가한 평면변형률 시험의 단부 구속 효과)

  • Jang, Eui-Ryong;Choo, Yoon-Sik;Lee, Won-Taeg;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.24 no.7
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    • pp.25-36
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    • 2008
  • The plane strain test can reproduce the real field condition and failure behavior precisely over other laboratory shear tests. Accordingly, this test has been utilized to investigate the shearing behaviors associated with overall failure behavior and local deformation of soils. However, most plane strain tests have been carried out with restrained end plates due to difficulties in manufacturing the equipment and also performing it. This restraint induces different results with real field because of shear stress on end plates. In this study, plane strain tests with/without bottom plate restraint were performed on Jumunjin-sand. The measurement of overall and local deformation was accomplished by digital image correlation technique as well as external LVDT. By applying digital image correlation method using two consecutive images captured through the transparent wall, local deformation behavior of various parts inside the specimen was estimated. And the formation and development of shear band caused by the restrained effect of end plate and the deformation mechanism of sand under plane strain condition were examined.

Behaviour of Foundation Ground with Marine Clay in Anisotropy (이방성을 갖는 해성점토 기초지반의 거동해석)

  • Kim, Myeon-Su;Lee, Kang-Il;Kim, Chan-Ki;Yun, Jung-Mann;Baek, Won-Jin
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.1
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    • pp.11-21
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    • 2015
  • This study aims at investigating of the behavioral characteristics of foundation ground subjected to a strip load in anisotropy. Using marine clays sampled at Shihwa area, a series of laboratory tests including triaxial compressive test, plane strain compressive and expansion tests that allows horizontal deformation only and zero strain (${\varepsilon}_2$) in the direction of intermediate stress (${\sigma}_2$) are conducted. In addition, a numerical analysis using parameters obtained from the tests is carried out. In the numerical analysis, Cam-clay model that simulates the behavior of natural deposited clay properly is adopted. The analysis results show that the vertical displacements of the plane strain compressive tests are relatively larger than those of triaxial compressive tests by 18-25%. Likewise, the horizontal displacements is 13-19% larger.

Consolidated Undrained Triaxial on Cubical Compression and Plane Clay Specimen (입방체 점토시료에 대한 압밀 비배수 삼축압축 및 평면변헝률 시험)

  • 박경기;이강일
    • Geotechnical Engineering
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    • v.10 no.3
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    • pp.41-54
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    • 1994
  • This study aims at investigating the mechanism and operation of cubical triaxial test developed by Lade in order to obtain analysis on the clayey foundation deformation. A comparison on deviator stress, pore water pressure and stress path is made between test results of clay using the cubical consolidated undrained test as well as plane strain test.

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Application of Modelling Stress-Strain Relations (Part I) -Application to Plane Strain Compression Tests- (응력-변형률 관계 정식화의 적용성(I) -평면변형률압축시험에 대한 적용성-)

  • Park, Choon-Sik
    • Journal of the Korean Geotechnical Society
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    • v.28 no.12
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    • pp.17-25
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    • 2012
  • FEM requires the stress-strain relationship equations for numerical analyses. However, most formulations for the stress-strain relationship published up to the present are not satisfactory enough to properly express all the levels from the small strain to the peak. Tatsuoka and Shibuya (1991) suggested a new single formulation applicable not only to a wide range of geo-materials from soft clay to soft rock, but also to a wide range of strain levels from $10^{-6}$ to $10^{-2}$. The plain strain compression test is carried out to seven samples of research standard sand specimens and two samples of glass beads, which have been used at world-renowned research institutes. In this study, strains of the maximum principal stress (${\sigma}_1$) and the minimum principal stress (${\sigma}_3$) were thoroughly measured from $10^{-6}$ to $10^{-2}$, and the result, applied to Tatsuoka and Shibuya's new formulation, coincided closely with the measured data of the stress-strain relationship from the small strain to the peak.

Failure Mechanism Evaluation in Normally Consolidated Cohesive Soils by Plane Strain Test with Digital Image Analysis (평면변형률 시험에서 디지털 이미지 해석을 통한 정규압밀 점성토의 파괴거동 분석)

  • Kwak, Tae-Young;Kim, Joon-Young;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.32 no.3
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    • pp.49-60
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    • 2016
  • Soil failure is initiated and preceded by forming and progressing of shear band, defined as the localization of deformation into thin zones of soil mass. To understand the failure mechanism of normally consolidated cohesive soil, the spatial distribution and evolution of deformation within the entire specimen need to be evaluated. In this study, vertical compression tests under plane strain condition were performed on reconstituted kaolinite specimens, while capturing digital images of the specimen at regular intervals during shearing. Overall stress-strain behavior from initial to post peak has been analyzed together with spatial distributions of deformations and shear band characteristics from digital images at 4 stages.

Deformation and Strength Characteristics of Compacted Weathered Granite Soil under Pland Strain Condition (평면변형률 조건에서 다짐화강토의 변형과 강도특성)

  • 정진섭
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.41 no.2
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    • pp.70-79
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    • 1999
  • The lower ground of structure, in which the strip loads, such as earth dams and embankments , are signiificantly working on , is required to be interpreted as a state of plane strain where the strain of intermediated principal stress direction is put '0' . The plane strain state is frquently observed in actural soil engineering case. For those case, drained stress-strain and strength behavior of Iksan weathered granite soil prepared in cubical specimens with cross-anisotropic fabric was studied by conventional triaxial compression, plane strain and cubial triaxial tests with independent control of the three principal stress. All specimens were loaded under conditions of principl stress directions fixed and aligned with the directions of the material axes. As a result of research , when a ground condition is analyzed under plane strain state, the shear strength obtained from the conventional triaxial compression test can be understimated.

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Anisotropy in Strength and Deformation Properties of a Variety of Sands by Plane Strain Compression Tests(Part II) -Deformation Characteristics at Extremely Small Strain Level (평면변형률압축시험에 의한 각종 모래의 강도.변형특성의 이방성(II)-미소변형률에서의 변형특성 이방성)

  • 박춘식;장정욱
    • Geotechnical Engineering
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    • v.14 no.4
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    • pp.33-46
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    • 1998
  • Anisotropy of stiffness, from extremely small strains to post-failure strains, of isotropically consolidated air-pluviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain at the specimen boundaries. It was found that the maximum Young's modulus $E_{max}$ was irrespective of the angle $\delta$ of the $\delta_1$ direction relative to the bedding plane. However, the normalized$ E_{max}$ was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness was increased as $\delta$ decreased.

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Investigation of Plane Strain Fatigue Crack Growth Behavior by Using Side-Grooved Specimens (측면홈 시험편을 이용한 평면 변형률 피로 균열 진전에 관한 연구)

  • 김종한;송지호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.1
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    • pp.63-69
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    • 1992
  • Plane-strain fatigue crack growth behavior of 7075-76 aluminium alloy was investigated by using side-grooved through-thickness center cracked tension(CCT) specimens. The effect of side-groove on the stress intensity factor value was examined. The effective thickness expression of $B_{e}$= $B_{o}$-( $B_{o}$-( $B_{ o-B_{n}^{2}}$ $B_{o}$ is the most appropriate to evaluate the stress intensity factor of side-grooved CCT specimen for fatigue testing. Fatigue crack growth rates can be well described by the effective stress intensity factor range based on closure measurements, for both side-grooved and uniform thickness specimens. Provided that the thickness of specimen meets the requirements for valid plane-strain fracture toughness, uniform thickness specimen data may be assumed to approximately represent the plane strain through-thickness crack growth behavior.ehavior.r.

Anisotropy in Strength and Deformation Properties of a Variety of Sands by Plane Strain Compression Tests(Part III) -Shear Deformation Characteristics- (평면변형률압축시험에 의한 각종 모래의 강도.변형특성의 이방성(III) -전단변형 특성-)

  • 박춘식;황성춘;장정욱
    • Journal of the Korean Geotechnical Society
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    • v.16 no.4
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    • pp.95-105
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    • 2000
  • Anisotropy of stiffiness, from extremely small strains to post-failure strains, of isotropically consolidated air-pulviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain relationships for a wide range of strain from about 0.0001% to 10% were obtained with measuring axial and lateral strains locally free from the effects of bedding and membrane penetration errors at the specimen boundaries. It was found that the maximum shear modulus Gmax was irrespective of the angle $\delta$of the $\sigma$1 direction relative to the bedding plane. However, the normalized Gmax was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness increased as decreased.

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