• 한국지반환경공학회 논문집
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• 제6권1호
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• pp.23-31
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• 2005

실트폰드는 크기가 55만평의 인공연못 안에 두께가 3~20m의 초연약점토가 침전되어 있었다. 1990년대 중반에 매립이 시작되었다. 매립 전 시료채취 및 다양한 종류의 원위치시험을 수행하였다. 실트폰드에 침전되어 있는 흙은 극도로 연약하기 때문에 모래 포설장비를 이용하여 모래를 전 지역에 균등하게 살포하였다. 대단히 주의 깊은 시공에도 불구하고 모래 포설시 대규모 전단파괴가 발생하였다. 따라서 파괴지역에 보강을 위하여 가로가 900m이고 세로가 700m인 고강도 보강매트를 포설한 후 재차 모래를 포설하여 매립을 완료하였다. 매립의 성공은 수중 콘관입시험으로 확인하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.119-122
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• 2009

The gravel compaction pile method has been used as a soft foundation improvement method because bearing capacity and discharge capacity is excellent. But the discharge capacity decreased when the clogging was generated because the clay penetrate into a void of gravel compaction pile. Accordingly, the purpose of this study is to reduce the clogging generation in gravel compaction pile constructing in the soft ground and take a step to minimize a void of gravel compaction pile. And the proper mixing ratio was determined with the large scale direct shear test performed to get strength and permeability with mixing ratio of crushed stone and sand(100:0, 90:10, 85:15, 80:20, 75:25). As a result of the test, it was showed that internal friction angle was the highest at 85:15 mixing ratio of crushed stone and sand and we can make sure a tendency of internal friction angle's decrease when the mixing ratio of crushed stone and sand passed 15%.

• 한국지반신소재학회논문집
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• 제8권3호
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• pp.1-7
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• 2009

지오그리드 보강재는 여러 토구조물에 널리 적용되어진다. 일반적으로 보강토 기초의 극한지지력은 강소성이론 이나 한계평형이론에 의하여 설명된다. 강소성이론 이나 한계평형이론에서는 보강재 또는 기초지반에 발생되는 파괴변형이나 변형율에 대하여 정확한 해석을 얻을 수 없다. 본 논문에서는 연약층위의 보강토 기초지반에 대하여 수치해석방법을 이용하여 자세한 파괴변형거동에 대하여 조사하였다. 보강재의 개수, 길이, 깊이 등을 포함하여 연약층위의 보강토 기초에 대하여 일련의 수치해석을 수행하였다. 유한요소프로그램을 사용하여 보강토기초에 대한 파괴거동 및 지지력의 향상효과에 대한 유효성이 조사되었다.

• 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.

• 한국지반공학회지:지반
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• 제14권6호
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• pp.81-92
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• 1998

앵커로 지지된 토류벽의 거동 해석기법에는 한계평형이론해석 (Limit Equilibrium Analysis), 유한요소해석(Finite Element Analysis), 그리고 탄소성보 해석법(Beam on Elasto-Plastic Foundation) 등이 있다. 이 중에서 탄소성보 해석법은 토류벽체의 변위, 휨모멘트, 토압분포 등을 구할 수 있고 유한요소해석에 비해 입력자료가 간편한 장점으로 인하여 널리 사용되어 왔다 (Haliburton. 1968.; Pfister등.. 1982: Briaud와 김 낙경, 1998), 탄소성보 해석법은 토류벽체를 탄성보로 모델링하고 지반을 탄소성 토압-변위 곡선 (Elasto-Plastic p-y Curve)으로 표시되는 스프링으로 모델링 하여 지반-토류벽 상호작용을 해석하는 기법이다. 그러므로 앵커토류벽의 탄소성보 해석법은 실제 거동을 모사할 수 있는 토압-변위 곡선의 구성 여부에 따라 그 해석 결과가 좌우된다. 본 논문에서는 미 국립토질시험장(U.S. National Geotechnical experimentation Site)에서 시공된 앵커토류벽의 변위,휨모멘트 계측자료로부터 Cubic Spline 함수를 이용하여 시공단계별로 토류벽에 작용하는 토압을 산정함으로서 토압-변위 곡선을 구성하였다. 구성된 토압-변위 곡선을 이용하여 탄소성 보해석을 실시하여 실측된 변위 및 휨모멘트와 비교함으로서 실험적인 토압-변위 곡선을 평가하고 시공단계를 적절히 고려할 수 있는 탄소성보 해석기법을 제안하였다.

• 한국지진공학회논문집
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• 제20권5호
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• pp.285-293
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• 2016

Soil-foundation-structure interaction (SFSI) is one of the important issues in the seismic design for evaluating the exact behavior of the system. A seismic design of a structure can be more precise and economical, provided that the effect of SFSI is properly taken into account. In this study, a series of the dynamic centrifuge tests were performed to compare the seismic response of the single degree of freedom(SDOF) structure on the various types of the foundation. The shallow and pile foundations were made up of diverse mass and different conjunctive condition, respectively. The test specimen consisted of dry sand deposit, foundation, and SDOF structure in a centrifuge box. Several types of earthquake motions were sequentially applied to the test specimen from weak to strong intensity of them, which is known as a stage test. Results from the centrifuge tests showed that the seismic responses of the SDOF structure on the shallow foundation and disconnected pile foundation decreased by the foundation rocking. On the other hand, those on the connected pile foundation gradually increased with intensity of input motion. The allowable displacement of the foundation under the strong earthquake, the shallow and the disconnected pile foundation, have an advantage in dissipating the earthquake energy for the seismic design.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.78-89
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• 2007

Two design examples of deep foundations for high-rise buildings on soft ground are introduced in this paper. The first one is a 54-story building in Ho-Chi-Minh city, Vietnam, which was designed to be founded on $2.8m{\times}1.0m$ barrette foundations with approximately 60m to 75m depth. Based on a number of design guides and existing load test data from the construction sites in Ho-Chi-Minh city, the capacity of a barrette foundation in sand or clay layered ground was calculated to be 17.2MN to 27.8MN depending on the installing depth. The second one is a 40-story building in Baku city, Azerbaijan, which was designed to be supported by 2.0m diameter bored pile foundations with approximately 23m depth. As analytical or empirical guides for the local ground conditions were very limited, the design procedure from the SNiP Code, one of Russian specifications, was adopted and used to calculate the pile capacity. The capacity of bored pile foundation in highly weathered soil was expected to be 14.8MN to 15.5MN depending on the boring depth.

• Earthquakes and Structures
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• 제25권2호
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• pp.135-148
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• 2023

The structure-soil-structure interaction (SSSI) effect in adjacent structures may affect the liquefaction-induced damage of shallow foundation structures. The existing studies only analysed the independent effects on the structural dynamic response but ignored the coupling effect of height difference and distance of adjacent structures (F) on liquefied foundations on the dynamic response. Therefore, this paper adopts finite element and finite difference coupled dynamic analysis method to discuss the effect of the F on the seismic response of shallow foundation structures. The results show that the effect of the short structure on the acceleration response of the tall structure can be neglected as F increases when the height difference reaches 2 times the height of the short structure. The beneficial effect of SSSI on short structures is weakened under strong seismic excitations, and the effect of the increase of F on the settlement ratio gradually decreases, which causes a larger rotation hazard. When the distance is smaller than the foundation width, the short structure will exceed the rotation critical value and cause structural damage. When the distance is larger than the foundation width, the rotation angle is within the safe range (0.02 rad).

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.192-200
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• 2010

Korea is part of a region of low or moderate seismic zone in which few earthquakes have been monitored, so it is difficult to approve design ground motions and seismic responses on structures from response spectrum. In this study, a series of dynamic centrifuge model tests for demonstrating seismic amplification characteristics in soil-foundation-structure system were performed using electro-hydraulic shaking table mounted on the KOCED 5.0 m radius beam centrifuge at KAIST in Korea. The soil model were prepared by raining dry sand and $V_S$ profiles were determined by performing bender element tests before shaking. The foundation types used in this study are shallow embedded foundation and deep basement fixed on the bottom. Total 7 building structures were used and the response of building structures were compared with response spectrum from the acceleration records on surface.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1819-1826
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• 2007

This study results of performed field load test in order to estimate the best pile length assessment and allowable bearing capacity of the pile foundation. End of initial driving(EOID) and restrike of pile dynamic loading tests were performed to calculate allowable bearing capacity of the experimental pile side and results were compared with the allowable bearing capacity estimated by theory. The results of allowable bearing capacity by EOID test is $1.08{\sim}1.21$ in the range of compared to the capacity calculated by the Structure Foundation Design Criterion. Allowable bearing Capacity by restrike of pile dynamic loading test is $1.32{\sim}1.48$ in the range of compared to the Structure Foundation Design Criterion. The Foundation Design Criterion underestimated the pile capacity. If the bearing capacity calculated by Structure Foundation Design Criterion is 100, EOID of pile dynamic loading test is 116, restrike of pile dynamic loading test is 138 for 20m pile used in this experimental.