• 한국지반공학회논문집
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• 제37권7호
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• pp.25-34
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• 2021

연약지반으로 이루어진 준설매립부지는 지반이 매우 연약한 상태이기 때문에 설계시 정확한 지지력을 계산하는 것은 어렵고 복잡한 요인들이 고려되어야 한다. 최근까지 준설매립지를 대상으로 다양한 연약지반처리공법을 설계하고 있지만, 초기 장비진입을 위해서 기존 Meyerhof(1974) 복합토층 지지력 계산으로 안전율을 예측하고 있다. 기존 방정식들은 시공성 안전을 확보한다는 차원에서 연약지반 지지력을 과소평가하여 경제적 비용이 증가될 수 있다. 따라서 본 연구에서는 현장여건이 고려된 지지력 식을 제안하였다. 이를 위하여 이론적인 방정식에서 고려되지 못하는 토목섬유의 봉합사 역할과 봉합인장강도가 지지력에 끼치는 영향을 실험으로 제시하여 적절한 연약지반 지지력을 평가할 수 있도록 제시하였다. 그리고, 현장시험으로 수정방정식 지지력의 안정성이 평판재하시험으로 실측한 값과 비교하여 적절성을 확인하였다. 향후 준설토 매립지반의 설계와 시공시 본 연구 결과가 기초자료로 활용될 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1312-1319
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• 2006

This thesis studied the scale effects on bearing capacity and settlement characteristics by using FEM. The conclusions of the study are as follows. 1) For sandy soil, the bearing capacity ratio increased in the form of logarithm as the foundation width increased. Hence application of static mechanic theory results in overestimation of the bearing capacity when the bearing capacity should be derived from plate loading test results. 2) In clayey soil, the characteristics of the bearing capacity associated with foundation width met Terzaghi's bearing capacity theory. 3) In sandy soil, the settlement ratio increased non-linearly as foundation width increased. However, in clayey soil, the settlement ratio increased linearly. 4) In ordinary soil, the foundation width - settlement ratio turned out to be close to that of sandy soil.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.977-982
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• 2000

As a newly structural system, RCS composite system has been researched last two decades. However mechanism of exterior T-type joint for RCS composite system is not well known. This research is focus on the exterior T-type joint for RCS composite system. Specimens are designed by the ASCE guideline, tested and compared with the inner RCS joint. Test variables include face bearing plate(FBP), extended face bearing plate(E-FBP) and U-bar. The tests indicate that the strength of exterior T-type joint is higher than that of the guideline by ASCE. The U-bar has a significant effect on the joint strength and absorbing the strain energy.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.21-22
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• 2005

A study on the wear characteristics of the white metal(Sn-base alloy) bearing as a function of particle contamination level was conducted in order to establish control criteria of the lubricant in the 2-stroke marine diesel engine. Particle contamination level of the lubricants ranged from NAS 10 to 12 for the experiments. Bar-on-plate type wear test was performed using reciprocating wear tester. Based on this study it was found that there was no noticeable difference in weight loss of the white metal for NAS10 and NAS11(particle contamination level). Surface roughness of the white metal bearing after the wear test of 8hrs for the highly contaminated lubricant(NAS12 level) was up to $6{\mu}m$ in Rmax whilst that of the less contaminated lubricants(NAS10 & 11) was less than $1.5{\mu}m$ in Rmax.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.347-352
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• 2002

Recent trends in the construction of building frame feature the increase use of composite steel concrete members functioning together in what terms of mixed structural systems. One of such systems, RCS(reinforced concrete column and steel beam) system is introduced and closely examined focusing on bearing strength of the composite joint in this paper. The main objective of this study was to develope one of details to increase bearing capacity while bearing failure is one of the two primary modes of failure in RCS system. Local bearing tests with specimens about 1/3 of the actual concrete column size were performed applying uniform load through steel plate with 100$\times$110mm size. Test results show that specimens with the bearing reinforcement detail developed in this study enhanced the bearing strength by 1.71~3.02 compared to concrete cylinder strength.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.747-754
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• 2010

The objective of this study is improve the technology by various testing devices for measuring degree of compaction. The methods for quality control for compaction are very various. But, normally the specifications have provided PBT(Plate Bearing Test) method when inspector tested quality control. In spite of the PBT has a few weak points to reduce process and cost. In order to improve quality control method, analyzed in-situ test results between PBT and other devices.(LWDT and Geogauge).

• 한국지반신소재학회논문집
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• 제8권1호
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• pp.33-40
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• 2009

본 논문에서는 도로를 보강하는 토목섬유 중 지오셀을 이용하였을 때의 보강효과를 알아보기 위해서 실내시험과 현장시험을 실시하였다. 실내 시험은 실대형 직접전단시험기와 모형토조 직접전단시험기를 이용하여 수직응력에 따른 전단응력 곡선을 산정하고 이를 통해 지오셀이 점착력과 내부마찰각을 증가하는 효과를 볼 수 있었다. 실내시험의 결과값을 Terzaghi 공식과 Meyerhof의 공식을 이용하여 극한지지력값을 계산하고 현장시험에서 확인한 극한 지지력값과 비교하여 지오셀의 보강효과를 확인하였다. 분석결과, 직접전단시험을 통해 지오셀의 보강효과가 내부마찰각의 증가에 영향을 미치는 것을 확인하였다. 또한 셀의 개수가 커질수록 내부마찰각이 커짐을 확인하여 보강면적이 넓을수록 보강효과가 증가하는 것으로 나타났다. 지지력에 미치는 영향요소중 내부마찰각을 증가시키는 지오셀을 도로저부에 시공할 경우 내부마찰각의 증가로 지지력 또한 증가하는 것을 확인하였으며, 평판재하시험의 결과값을 통해 지오셀보강이 극한지지력값의 증가효과에 2배정도의 보강효과를 확인하였다. 수치해석을 통해 변형의 분포와 침하량을 확인한 결과, 침하량은 지오셀에 의해 줄어드는 결과를 보여 침하에 대한 보강효과를 확인하였다.

• Structural Engineering and Mechanics
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• 제84권3호
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• pp.375-391
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• 2022

This paper discussed and analyzed the interfacial stress distribution characteristic of adjacent cracks in Carbon Fiber Reinforced Polymer (CFRP) plate strengthened concrete slabs. One un-strengthened concrete test beam and four CFRP plate-strengthened concrete test beams were designed to carry out four-point flexural tests. The test data shows that the interfacial shear stress between the interface of CFRP plate and concrete can effectively reduce the crack shrinkage of the tensile concrete and reduces the width of crack. The maximum main crack flexural height in pure bending section of the strengthened specimen is smaller than that of the un-strengthened specimen, the CFRP plate improves the rigidity of specimens without brittle failure. The average ultimate bearing capacity of the CFRP-strengthened specimens was increased by 64.3% compared to that without CFRP-strengthen. This indicites that CFRP enhancement measures can effectively improve the ultimate bearing capacity and delay the occurrence of debonding damage. Based on the derivation of mechanical analysis model, the calculation formula of interfacial shear stress between adjacent cracks is proposed. The distributions characteristics of interfacial shear stress between certain crack widths were given. In the intermediate cracking region of pure bending sections, the length of the interfacial softening near the mid-span cracking position gradually increases as the load increases. The CFRP-concrete interface debonding capacity with the larger adjacent crack spacing is lower than that with the smaller adjacent crack spacing. The theoretical calculation results of interfacial bonding shear stress between adjacent cracks have good agreement with the experimental results. The interfacial debonding failure between adjacent cracks in the intermediate cracking region was mainly caused by the root of the main crack. The larger the spacing between adjacent cracks exists, the easier the interfacial debonding failure occurs.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1166-1171
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• 2008

Despite of the increasing number of the application of drilled shaft piles in construction site, most studies on pile capacity have been focused on the side shear resistance. But it is common that the drilled shaft is socketed on the rock so as to use its bearing resistance. The prediction of the end movement and characteristics of the bearing capacity of the pile is great important as well. Therefore, a series of scaled model tests were carried out in order to study the characteristics of the bearing capacity on rock mass. The material of the test block was cement mortar which was mixed with sand, cement and water, and the size of a test block size was $240{\times}240{\times}240mm$. The axial load was applied by a miniaturized pile of 45mm in diameter and flat jacks and steel plate were used for confinement to simulate the real underground loading conditions. The relation of load-displacement was measured in various different conditions of rock mass such as strength, discontinuity of the rock mass and in-situ stress, so q-w curves of the end of the pile were presented for each condition.

• 한국지반환경공학회 논문집
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• 제11권4호
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• pp.51-59
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• 2010

본 연구는 준설 매립된 느슨한 상태의 실트질 사질토층이 얕게 분포해 있는 지역에 건물 조성 및 건축물 시공을 위한 기초설계사례에 관한 연구로, 연구 대상지는 군산, 인천지역의 준설 매립지로 심도 E.L(-)10m 전후에 느슨한 실트질 사질토층이 분포해 있으며, 하부 말뚝기초의 지지층은 E.L(-)20m 전후로 출현하고 있어 얕은 기초공법 적용 시 기초지반 보강을 위한 지반개량이 필요한 지역이다. 따라서 이에 적용 가능한 기초처리 공법들을 비교 검토한 결과 구역별 설계하중 조건을 고려하는 동다짐 공법이 가장 적합한 공법으로 선정되었다. 본 연구에서는 이를 검증하기 위한 방법으로 현장시험시공을 통해 시공결과에 대한 확인시추조사 및 평판재하시험 등을 실시하여 지반개량효과를 분석하였으며, 동다짐 공법에 의해 지지력에 대한 안정성이 확보됨을 확인하였다.