• 한국철도학회논문집
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• 제9권4호
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• pp.493-498
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• 2006

In this study, two large pile load tests were performed in the deep sand gravel deposit of Nakdong river basin so that the characteristics of the load transfer was identified. The fully instrumented rectangular barrette pile in the size of $1.5\times3.0m$ and the circular bored pile of the diameter 1.5 m were placed into the ground below 50 m. Under the applied loads of 2,400 tonf and 4,000 tonf, the test results of the load transfer showed the portion of 83% and 93% of the applied loads on the barrette pile and the bored pile, respectively, were supported by the skin friction along the pile shaft. It was revealed that the most of these skin friction mobilized in sand layer underlying clay layer having N-value more than 30 and that the friction per unit area of the bored pile was larger than the friction of barrette pile. However, if embedded in the stiff sand graval layer, the both piles were proven to be sufficient for using as the friction piles.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.528-535
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• 2005

Using the case of design to the Large diameter Bored Pile, We showed the various method to estimate the Lateral coefficient of subgrade reaction and analyzed the lateral displacement behavior according to the characteristics of sub layer distribution. According to the study, Mutual relation to the N value and the soil modulus of deformation showed 400N to 800N to the fine grained soil and weathered soil. It showed simular tendancy with the proposed expression of Schmertmann. But Weathered rock was over estimated as 4,200N. $k_h$ to the sedimentory soil and weathered rock each showed these orded of Schmertmann-PMT-2,800N and Schmertmann-2,800N-PMT. As the factor($\alpha$) 4 was applied to the estimation in weathered rock, $k_h$ to the PMT was calculate as a big value. If the pile is long and the pile is surpported to the soil, Lateral displacement was in inverse proportion ratio to the value of $k_h$. But the case of shallow soil layer(early bedrock) and the short pile, Lateral displacement was affected by the behavior of socheted pile to the bedrock not by the upper soil layer.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.145-156
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• 2009

Large diameter bored pile was selected as the foundation type for Taipei 101. The pile construction method and specific construction procedures were determined based on the results of trial installation and pile load tests. The baseline for foundation design was established using the friction versus depth characteristics of each ground layer obtained from the pile load tests. As the ground profile and depth to the top of rock formation varied significantly on this site, the pile length, bearing capacity and settlement for single pile were analyzed using the information interpreted from adjacent boreholes. The post grouting at pile tip was mandatory for pile construction. Nevertheless, it was treated as a measure reducing the influence of construction uncertainties and providing extra safety for the foundation system.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.285-292
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• 2000

Though there has been increasing use of large diameter drilled shaft as a foundation structure of bridges, current practice for quality control is to confirm the minimum required load carrying capacity during construction stage. For economic and appropriate design of drilled shaft, it is necessary to evaluate the load transfer mechanism by pile load tests during initial stage of construction and to use the test results as a feedback to a revision of initial design. In this paper, results of load tests peformed at several domestic sites are presented to investigate the load transfer characteristics of large diameter drilled shaft. It was found that most of the load on piles is sustained by shaft friction and that only small portion of the load reaches the bottom of the drilled shaft. Some test results of drilled shaft by Pile Driving Analyzer performed at same sites are also presented to compare the load transfer characteristics interpreted from static pile load tests.

• 국제초고층학회논문집
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• 제4권4호
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• pp.261-270
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• 2015

Hong Kong is a renowned small city with densely placed skyscrapers. It is no surprise that heavy duty or even mega foundations are built over the years to support these structures. To cope with the fast construction pace, several heavy deep foundation types have been widely adopted with some prescribed design rules. This Paper has selected two commonly adopted but distinctive foundation types, namely large diameter bored piles and percussive steel H-piles to illustrate the special design and construction considerations related to these pile types in related to local context. The supervision requirement in related to foundation works for which again may be unique in Hong Kong will also be highlighted. A case history is also discussed in the later part of the Paper to illustrate the application of one of these foundations and to highlight the importance of considering foundation design and basement excavation method in a holistic manner.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.90-104
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• 2007

The trend of current urban redevelopment and new city development project shows that the superstructure of building is getting larger and higher in consequence of a limited plottage condition and the preference of landmark. For this reason, it is definitely required to extend pile diameter and install the pilein deep foundation to support superstructure. The pile method causes construction-related problems such as increasing quantities, difficulty of storage & transportation material and decreasing design load while construct pile in deep foundation. The Bored Pile method has applied to minimize those problems. As above shown, this article will be presented construction case study of Barrette Pile and R.C.D in order to make a counterproposal for the quality control of a large building foundation work.

• 한국지반공학회논문집
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• 제28권6호
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• pp.19-29
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• 2012

일반마이크로파일의 저항성능을 개선시키기 위해 최근에 토목섬유을 활용한 팩마이크로파일이 개발되었다. 팩마이크로파일은 일반마이크로파일의 강봉이나 강관을 토목섬유팩으로 감싸고 주입재와 주입압을 토목섬유팩 내부에 가하여 제작한다. 이 주입압에 의하여 천공 직경이 크게 확대된다. 동일한 한 지반 속에 설치된 세 개의 마이크로파일을 대상으로 일련의 말뚝인발시험을 실시하였다. 세 말뚝 중 두 개는 팩마이크로파일였고 나머지 하나는 강봉을 사용한 일반마이크로파일이였다. 토목섬유팩에 적용된 주입압에 의하여 팩마이크로파일의 경우 천공직경이 152mm에서 220mm으로 확대되었다. 마이크로파일의 주면에서 발달하는 단위주면마찰력은 말뚝두부의 인발변위량의 증가와 함께 서서히 증가하여 한계상태에 도달한 한계변위량에서 수렴치에 도달한다. 팩마이크로파일의 인발저항력은 일반마이크로파일의 인발저항력보다 크게 나타난다. 이와 같은 팩마이크로파일의 인발저항력을 증대시킬 수 있는 원인으로는 크게 두 가지를 생각할 수 있다; 첫째는 마이크로파일에 설치한 토목섬유팩내 주입압으로 마이크로파일의 단면적을 증대시키므로 말뚝주면의 마찰저항면적을 증대시킬 수 있기 때문이고, 둘째는 마이크로파일의 단면이 확대될 때 확대되는 부분의 체적만큼의 토사가 주변지반을 압축시켜 말뚝과 지반 사이의 마찰저항력을 증대시킬 수 있기 때문이다. 이 압축효과는 지표면 부근 보다 깊은 지층에서 크게 나타났다. 말뚝 주면에서 발휘되는 단위주면마찰력은 말뚝의 직경이 작은 경우가 더 크게 발휘된다. 즉 마이크로파일의 주면에서 발달되는 단위주면마찰력은 대구경 현장타설말뚝의 주면에서 발달되는 단위주면마찰력보다 크게 나타난다.

• 한국지반환경공학회 논문집
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• 제14권3호
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• pp.41-49
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• 2013

회전관입형 말뚝은 말뚝설치 시 주변 흙의 변위가 발생하는 변위 말뚝으로 큰 지지력 및 인발력을 발휘할 수 있다. 또한 비배토 공법으로 슬라임이 발생하지 않고 시공 중 소음, 진동이 작아 환경친화적인 특성이 있어 외국의 경우 적용사례가 증가하고 있다. 하지만 대부분의 말뚝을 직접적으로 항타하는 항타말뚝, 선굴착 후 기 제작된 말뚝을 지중에 매입하는 매입말뚝이 주로 적용되고 있으며 회전관입형 말뚝의 사용은 제한적으로 이루어지고 있다. 지금까지 실시된 대부분의 실내시험에서는 말뚝을 설치한 후 지반을 조성하여 지지거동을 평가함에 따라 회전관입형 말뚝의 회전관입과정으로 인한 지지거동의 규명은 미흡한 실정이다. 이에 본 연구에서는 풍화토를 대상으로 회전관입과정을 모사한 실내실험을 실시하여 풍화토에 대한 지지력 거동을 평가하고자 하였으며, 더불어 나선형 판의 직경, 나선형 판의 간격, 나선형판의 개수, 나선형 판의 제원 등을 변화시켜가며 지지 거동을 평가하였다. 연구결과를 통하여 나선형 강관말뚝의 지지력 평가 결과 및 주요 제원에 따른 지지력 변화와 기존이론과의 비교분석 결과를 제시하였다.