• 한국지반공학회논문집
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• 제38권8호
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• pp.7-15
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• 2022

대부분의 선행연구는 동결 삼축압축시험 수행 시, 몰드를 사용하여 시료를 조성하고 단방향으로 동결을 진행하였다. 이는 동결된 시료에 잔류응력이 발생할 가능성이 있기 때문에 인공동결공법이 적용된 지반을 모사하는데 한계가 있다. 본 연구에서는 기존 시험방법의 한계를 보완할 수 있는 시험장비 및 시험방법을 제안하고, 제안된 방법으로 온도 및 구속압력에 따른 동결 사질토의 역학적 특성을 평가하였다. 동결온도가 낮아질수록 동결 사질토는 취성이 증가하였고, 부동수분의 감소 및 얼음자체의 강도 증가로 인하여 강도가 증가하였다. 구속압력의 증가는 강도저감 효과를 발생시키는 압력융해 현상과 강도증진 효과를 발생시키는 흙 입자의 마찰력 증가 모두를 야기하였다. 이처럼 동결 사질토의 역학적 거동은 구속압력과 동결온도의 복합적인 영향을 받는 것으로 나타났다.

• 한국농공학회지
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• 제41권2호
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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.

• KCI Concrete Journal
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• 제13권1호
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• pp.53-60
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• 2001

Tests of cylindrical concrete specimens under lateral confining pressure of up to 5,000 psi were conducted for two different axial loading cases: monotonic compression and monotonic tension. The purpose of this experimental investigation is to provide stress-strain characteristics of plain concrete in triaxial stress conditions. Lateral confining pressure levels, loading rates, and strength of concrete specimens are varied as parameters. The loading rates are $34.75$\times$10^{-5}$ in/in/sec for fast, $\times$$6.95x10^{-5}$ in/in/sec for normal. and $0.579$\times$10^{-5}$ in/in/sec for slow loading cases. The concrete specimens used in the experiment have compressive strength of 3,500 psi and 6,500 psi, respectively. Findings of this experiment include dependency of the stress-strain behavior of concrete on the above parameters under two different types of loading conditions. The parametric study includes a series of 106 triaxial tests.

• Geomechanics and Engineering
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• 제17권2호
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• pp.215-225
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• 2019

The mechanical behavior of rock is essential to estimate the capacity and long-term stability of $CO_2$ storage in deep saline aquifers. As the depth of reservoir increases, the pressure and temperature that applied on the rock increase. To answer the question of how the confining pressure and temperature influence the mechanical behavior of reservoir rock, triaxial compression experiments were carried out on brine-saturated sandstone at elevated temperature. The triaxial compressive strength of brine-saturated sandstone was observed to decrease with increasing testing temperature, and the temperature weakening effect in strength enhanced with the increase of confining pressure. Sandstone specimens showed single fracture failures under triaxial compression. Three typical regions around the main fracture were identified: fracture band, damaged zone and undamaged zone. A function was proposed to describe the evolution of acoustic emission count under loading. Finally, the mechanism of elevated temperature causing the reduction of strength of brine-saturated sandstone was discussed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.569-576
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• 2000

This study performs a series of Triaxial Compression Test for clay-sand composite specimens changing area replacement ratio. Purpose of the test is to conform the propriety of weighted average method in estimating shear strength of the composite ground. The test results show that measured values of shear strength of composite specimens are larger by 20∼30% than those from estimation using the current weighted average method. It is thought that the differences are from pseudo-overconsolidation behavior of composite specimens.

• 한국산학기술학회논문지
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• 제11권10호
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• pp.4012-4017
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• 2010

이 연구에서는 팩 말뚝과 모래다짐말뚝의 전단강도 특성을 비교하기 위해 모래-팩-점토 복합토 및 모래-점토 복합토를 인위적으로 치환율($a_s$) 10%, 20%로 재성형하여 구속압력을 변화시켜가며 삼축압축시험(CU Test)을 실시하였다. 시험결과 모래-점토 복합토에 비해 모래-팩-점토 복합토의 강도가 치환율 10% 및 20% 모두에서 훨씬 크게 측정되어 모래다짐말뚝보다 팩말뚝이 큰 지지력을 갖는다는 것을 확인하였다.

• 한국지반공학회논문집
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• 제18권1호
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• pp.29-39
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• 2002

본 연구에서는 미소변형률에서 파괴규준을 포함하는 대변형률에 이르는 전체 변형률 영 역의 거동을 획득하기 위하여, LVDT를 장착하여 국부변위를 측정한 삼축압축시험을 수행하였다. 이러한 결과 미소변형률(0.001% 수준)에서 대변형를까지(10%)의 거동을 합리적으로 구할 수 있었으며, 불교란 및 교란 풍화토 시료에서의 변형계수가 미소변형률 영역에서 유사하게 나타났다. 그리고 공진주(RC)시험과 비배수 삼축압축시험에서 구한 정규화 전단변형계수$(G/G_{max})$ 곡선이 일치한 반면 최대전단변형계수$(G/G_{max})$는 포화도에 따라 상이하게 나타났다. 또한 비등방경화 구성모델의 계수 연구를 통하여 전체 변형률 영역 거동을 합리적으로 예측할 수 있음을 확인하였다.

• Geomechanics and Engineering
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• 제10권1호
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• pp.37-48
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• 2016

The hyperbolic stress-strain model has been shown to be valid for modeling nonlinear stress-strain behavior for rockfill materials. The Duncan-Chang nonlinear constitutive model was adopted to characterize the behavior of the modeled rockfill materials in this study. Accurately estimating the model parameters of rockfill materials is a key problem for simulating dam deformations during both the dam construction period and the dam operation period. In order to estimate model parameters, triaxial compression experiments of rockfill materials were performed. Based on a genetic algorithm, the constitutive model parameters of the rockfill material were determined from the triaxial compression experimental data. The investigation results show that the predicted strains provide satisfactory precision when compared with the observed strains and the strains forecasted by a gradient-based optimization algorithm. The effectiveness of the proposed inversion procedure of model parameters was verified by experimental investigation in a laboratory.

• 한국도로학회논문집
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• 제15권2호
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• pp.83-94
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• 2013

PURPOSES : In Korea, most designs of pavement had been mainly performed by considering CBR of granular materials before KPRP(Korea Pavement Research Program) and 86 AASHTO design method were introduced. Since then, the trend of the pavement designs gradually have moved to using mechanical characteristics throughout the resilient modulus based on the test results up to recently. In this study, we should like to research the mechanical characteristics of paving materials containing Recycled aggregates through the cyclic loading triaxial compression tests. METHODS : The kinds of materials were tested; coarse grained subbase materials, refining aggregates base materials and recycled aggregates. RESULTS : The present study aims to figure out the resilient modulus of paving materials containing Recycled aggregates through the cyclic loading triaxial compression tests. CONCLUSIONS : The test results revealed that the engineering properties of the recycled aggregates were more excellent than the those of others.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1124-1131
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• 2008

Thanks to a new in-situ seismic probe, using bender elements and penetration scheme, a simple linear relationship between undrained shear strength(Cu) and shear wave velocity(Vs) was obtained. This priceless relationship is worthy to be illuminated further in ideal laboratory environment. To avoid sampling disturbance effect, special consolidation cylinders were used to make normally consolidated specimens from kaolinite suspension. The undrained shear strengths of the specimens were measured using unconsolidated undrained triaxial compression tests. Also shear wave velocity measurements were performedprior to shearing the same specimens, using the bender elements installed in the base pedestal and the top cap of the triaxial compression cell. The Cu-Vs relationship is fairly linear and supports the linear trend of clayey silt obtained using field testing. Also the classic density-shear modulus relationship for soft clay proposed by Hardin and Black(1969) was once more verified hereby.