• 한국지반환경공학회 논문집
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• 제2권4호
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• pp.51-61
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• 2001

본 논문에서는 지반의 상대다짐도(RC)와 매입말뚝의 근입비에 따른 하중-침하 거동을 연구하기 위하여 모형실험과 하중전이 함수를 이용한 해석을 수행하였다. 모형시험에서 말뚝은 근입비(L/D)를 15, 20, 25로 설치하였고, 지반의 상대다짐도를 85%, 95%로 각각 조성하였으며 말뚝주면은 시멘트를 주입하였다. 본 논문은 매입말뚝의 해석을 위하여 Vijayvergia의 하중전이 모델, Castelli 모델, Gwizdala의 탄소성-완전소성 모델, coyle의 제안식 등을 사용하여 실험결과와 비교하였으며, 매입말뚝의 하중-침하 거동을 예측하는데 가장 적합한 하중전이 방법을 제안하였다. 하중전이 함수에 의한 지지력 예측 결과 매입말뚝의 극한 지지력은 Coyle의 제안식이 실측값에 가장 근접한 것으로 나타났으며, 초기 하중-침하 거동은 Castelli에 의한 함수가 가장 유사하게 하중-침하 거동을 평가하는 것으로 나타났다. 매입말뚝의 축하중 해석결과 하중전이법에 의해 평가된 주면마찰력이 실측값보다 과소평가 되는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1351-1358
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• 2008

This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is quite open used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with the results of finite element analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 말뚝기초 학술발표회
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• pp.85-106
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• 2000

The load distribution and deformation of drilled shafts subjected to axial loads were evaluated by a load transfer approach. The emphasis was on quantifying the load transfer mechanism at the interface between the shafts and surrounding highly weathered rocks based on a numerical analysis and small-scale tension load tests performed on nine instrumented piles. An analytical method that takes into account the soil coupling effect was developed using a modified Mindlin's point load solution. Based on the analysis, a single-modified hyperbolic model is proposed for the shear transfer function of drilled shafts in highly weathered rocks. Through comparisons with field case studies, it is found that the prediction by the present approach is in good agreement with the general trend observed by in-situ measurements.

• 한국지반공학회논문집
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• 제25권8호
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• pp.77-93
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• 2009

본 연구에서는 3차원 유한차분해석을 통하여 말뚝직경, 암반물성, 불연속면의 간격 및 방향 등 주요 인자가 암반근입 현장타설말뚝의 선단거동에 미치는 영향에 대한 분석을 수행하였으며, 이를 토대로 초기기울기 및 극한 단위선단지지력을 변수로 하는 쌍곡선형태의 선단하중전이(q-w)함수를 제안하였다. 제안식의 국내 암반지반에의 적용을 위하여 국내에서 수행된 14개 현장 23본의 시험말뚝의 재하시험자료를 토대로 제안식의 경험계수를 산정하였으며, 더불어 기존 초기기울기 및 극한단위선단지지력 산정식의 타당성 검토도 수행하였다. 현장재하시험 사례와의 비교분석 결과, 본 연구에서 제안된 산정식은 국내 암반지반에 근임된 현장타설말뚝의 선단거동을 비교적 잘 예측 가능하고, 말뚝지지력 및 침하량 예측값이 실측값에 가까움을 알 수 있었다.

• 한국지반공학회지:지반
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• 제14권2호
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• pp.93-106
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• 1998

축하중 재하시 실제 강관말뚝의 거동을 API 하중전이 곡선을 이용한 유한차분해석과 FLAC 프로그램을 이용한 수치해석으로 분석하였다. 실험적으로 계측한 말뚝두부의 하중-변위 관계와 깊이에 따른 축하중 분포를 적합하게 예측할 수 있었다. 특히, FLAC 프로그램 해석결과에서는 하중 제거시 매립층에서 응력 경로가 파괴 포락선 상에서 발생하여 비선형적인 하중-변위 관계를 매우 유터사하게 예측할 수 있었다. 또한 FLAC 프로그램 해석결과 및 API 규준에 따른 하중전이 관계를 실험결과와 비교하여, 말뚝-지반간 전이거동을 분석하였다. 사례연구를 통하여 API 하중전이관계를 이용한 유한차분해석이나 FLAC 프로그램을 이용한 수치해석으로 축하중 재하 말뚝의 공학적인 거동을 합리적으로 평가할 수 있음을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1188-1194
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• 2008

As computation technologies has developed, the analysis using load transfer is mainly performed. But most of the functions used in the above program has been developed in foreign countries. Also in our nation, lots of studies concerning load transfer are being researched. The investigation of suitability about the piles installed in our grounds, however, is required as functions acquired experientially, basing on the piles installed in foreign grounds. In this background, the load transfer curve required to use load transfer method on its design through the analysis of field tests inside our nation intends to be made, on which this research focuses.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.539-550
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• 2009

As computation technologies has developed, the analysis using load transfer is mainly performed. But most of the functions used in the above program has been developed in foreign countries. Also in our nation, lots of studies concerning load transfer are being researched. The investigation of suitability about the piles installed in our grounds, however, is required as functions acquired experientially, basing on the piles installed in foreign grounds. In this background, the load transfer curve required to use load transfer method on its design through the analysis of field tests inside our nation intends to be made, on which this research focuses.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.760-766
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• 2008

As computation technologies has developed, the analysis using load transfer is mainly performed. But most of the functions used in the above program has been developed in foreign countries. Also in our nation, lots of studies concerning load transfer are being researched. The investigation of suitability about the piles installed in our grounds, however, is required as functions acquired experientially, basing on the piles installed in foreign grounds. In this background, the load transfer curve required to use load transfer method on its design through the analysis of field tests inside our nation intends to be made, on which this research focuses.

• 한국물환경학회지
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• 제26권6호
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• pp.1008-1015
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• 2010

Discharged pollution load is varied as rainfall changes in the area with combined sewer system. Changes in discharged pollution load are directly related with those of sewer transfer flow. Therefore, it is important to identify the pattern of sewer transfer flow for the analysis of changes in discharged pollution load. This study reviewed the type of distribution of sewer transfer flow for 17 sewage treatment plants and developed simple formular to estimate sewer transfer flow as rainfall changes. 11 facilities showed to have some relation with rainfall in the change of sewer transfer flow but 6 facilities to have no relation. Relationships between rainfall amount and sewer transfer flow showed that 6 facilities out of 11 had relatively strong relationships above R2=0.5, which were considered to be affected directly by rainfall changes. The formular which explain the relationship between rainfall and sewer transfer flow can be applied in the analysis of rainfall effects on discharged pollution load, therefore, the more appropriate evaluation will be done.

• Geomechanics and Engineering
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• 제10권6호
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• pp.737-755
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• 2016

The load transfer depth of a ground anchor is the minimum length required to transfer the initial prestressing to the grout column through the bonded part. A thorough understanding of the mechanism of load transfer as well as accurate prediction of the load transfer depth are essential for designing an anchorage that has an adequate factor of safety and satisfies implicit economic criteria. In the current research, experimental and numerical studies were conducted to investigate the load transfer mechanism of ground anchors based on a series of laboratory and field load tests. Optical FBG sensors embedded in the central king cable of a seven-wire strand were successfully employed to monitor the changes in tensile force and its distribution along the tendons. Moreover, results from laboratory and in-situ pullout tests were compared with those from equivalent case studies simulated using the finite difference method in the FLAC 3D program. All the results obtained from the two proposed methods were remarkably consistent with respect to the load increments. They were similar not only in trend but also in magnitude and showed more consistency at higher pullout loading stages, especially the final loading stage. Furthermore, the estimated load transfer depth demonstrated a pronounced dependency on the surrounding ground condition, being shorter in hard ground conditions and longer in weaker ones. Finally, considering the safety factor and cost-effective design, the required bonded length of a ground anchor was formulated in terms of the load transfer depth.