• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.44-57
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• 2010

The purpose of this paper is to introduce case studies on 2 projects for the construction of port facilities in Colombo, Sri lanka. In Queen Elizabeth quay development project in 2000, the damage at the bottom of steel tubular piles were occurred when piles were driven into subsoil for piled wharf structure in Stage 1. In order to prevent same incident in Stage 2 & 3, the pile driveability analysis were executed by dynamic formulas, analysis program, test driving and pile load tests. Through pile driveability analysis, prevention plans were proposed. In Colombo port expansion project in 2008, the mv method was applied to predict a primary consolidation settlement of a subsoil under a breakwater in the calculation stage. The $m_v$ was estimated from results of cone penetration tests and the final settlement by consolidation was calculated with it.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.70-77
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• 2010

In this paper, a case study of drivability and bearing capacity of large diameter steel pipe piles at PTT LNG site in Thailand is introduced. The LNG facilities were designed to be founded on steel pipe pile foundations driven into the weathered rock formation overlaid by sand layers. The drivability analyses of open ended pipe piles were carried out using GRL WEAP program and the bearing capacities of the piles were estimated. Dynamic load tests were performed to evaluate end bearing resistance, and it is shown that the measured end bearing resistance is smaller than the calculated end bearing because the plugging does not develop sufficiently in case of large diameter pipe piles.

• Geomechanics and Engineering
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• 제11권1호
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• pp.59-76
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• 2016

Penetration problems in geomechanics are common. Usually the soil is heavily disturbed around the penetrating bodies and large deformations and distortions can occur. The simulation of the installation of displacement piles is a good example of the interest of these types of problems for geomechanics. In this paper the Material Point Method is used to overcome the difficulties associated with the simulations of problems involving large deformation and full displacement type penetration. Recent modifications of the Material Point Method known as Generalized Interpolation Material Point and the Convected Particle Domain Interpolation are also used and evaluated in some of the examples. Herein a footing submitted to large settlements is presented and simulated, together with the processes associated to a driven pile under undrained conditions. The displacements of the soil surrounding the pile are compared with those obtained by the Small Strain Path Method. In addition, the Modified Cam Clay model is implemented in a code of MPM and used to simulate the process of driving a pile in dry sand. Good and rather encouraging agreement is found between compared data.

• 한국항해항만학회지
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• 제26권1호
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• pp.106-111
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• 2002

말뚝에 대한 지지력 평가는 재하시험에 의한 결과를 이용하는 것으로부터 정.동력학적 공식등 다양한 방법들이 사용되고 있다 최근의 국내 조사에 의하면 표준관입시험의 N치에 기초한 Meyerhof공식이 설계단계에서 빈번하게 사용되는 것으로 보인다. 본 연구에서는 국내에서 실시된 다수의 정 동재하시험자료를 가지고 말뚝기초 설계에 사용되는 이론식을 실측값과의 비교를 통해 각종 이론식에 의한 말뚝의 허용지지력 추정의 신뢰성을 알아 보고자 하였다 또한, 경시효과를 고려한 경우 말뚝의 지지력에 미치는 영향에 대해서도 연구가 이루어졌다 본 연구를 통해 얻은 주요 결과로는 Davisson 방법을 기준으로 정도를 평가한 결과, Terzaghi & Peck > Chin > Meyerhof > 수정 Meyerhof 방법순으로 기준값에 근접하였으며 동재하시험결과는 항타공식 중 수정 Engineering News 공식이 가장 실측치에 근접한 결과를 주었으나 이는 해머 효율의 불확실성이라든가 변수의 자체특성, 경시효과등이 고려된 경우에는 다른 결과를 줄 수도 있을 것으로 판단되며, 경시효과를 고려한시험 결과 선단지지력에 비해 주면마찰력이 뚜렷하게 증가하였는데 항타시 대비 주면마찰력은 평균 약 2배정도 증가하였고 Engineering News,수정 Engineering News, Hiley, Danish, Gates, CAPWAP 해석시에 대한 7일의 경시효과를 고려한 관계시은 각각 $Q_{u(Restrike)} / Q_{u(EOID)} = 0.98t_{0.1}$ , $0.98t_{0.1}$, $1.17t_{0.1}$, $0.88t_{0.1}$, $0.89t_{0.1}$, $0.97t_{0.1}$.과 같은 결과를 주었다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권2호
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• pp.130-137
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• 2017

최근 경제 성장과 건설 기술의 발달로 인해 구조물이 대형화, 고층화됨에 따라 상부구조물을 지지할 수 있는 기초의 역할이 중요시 되고 있다. 이 연구에서는 철근콘크리트 말뚝 성능향상을 목적으로 프리캐스트공법과 철근 및 속채움 콘크리트로 말뚝머리부를 보강한 철근 콘크리트 말뚝(HPC)을 개발하고 한계상태설계법을 바탕으로 말뚝성능을 예측하였고 설계와 실제강도와 비교를 통해 말뚝 내력의 안전성을 평가하였다. HPC말뚝 본체의 단면형상은 최대폭 500 mm, 최소폭 475 mm의 10각 단면으로 말뚝머리부 본체 두께는 70 mm이다. 중공부 본체 내측은 도로교설계기준에서 제시하는 수평전단강도를 확보하기 위해 요철형상으로 제작하였다. 전단강도 실험 결과 사인장균열이 발생하였지만 최종 파괴단계까지 급격한 파괴 없이 안정적인 전단내력을 확보하였고 한계상태설계법으로 예측한 전단강도를 135%, 119% 상회하였다. 말뚝머리 본체부 두께에 가외철근 보강 유무에 따라 제작된 실험체의 항타실험 결과 모든 말뚝 실험체에 균열이 발생하지 않아 충격에 대한 저항이 우수한 것으로 나타났다. 기성 PHC말뚝과 HPC말뚝 연결부 휨실험을 통해 측정된 휨하중을 평가한 결과 기성 PHC말뚝 설계 휨균열 하중에 비해 1.51배 및 1.48배 높은 값을 나타내어 충분한 연결부 휨내력을 확보하는 것으로 나타났다.

• 대한기계학회논문집A
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• 제28권6호
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• pp.763-773
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• 2004

This paper suggests the 2 D.O.F mathematical model of the High Frequency Vibro-Hammer (HFVH), introduces an experimental method for measuring of the attenuation of piling vibration and proves what experiments are coincident with the equation of wave propagation. As vibratory installation of piles and casings has many economic merits in the construction field, most of all contractors prefer to vibratory pile driving method than the other. Compared to impact pile driving, vibratory installation has the advantage of reducing vibration or noise pollution and can drive piles under high frequency. Experiments serve estimations of capabilities and limitations of the HFVH's excitation force and finding of sensitivity for important soil resistance parameters. Also, we discuss the HFVH that can drive with three kinds of input waves (triangular, sine and square wave) and propose the design of parameters to improve actuating performance in it.

• 한국소음진동공학회논문집
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• 제21권4호
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• pp.299-306
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• 2011

This study investigated the SIP-method as a low-vibration, low-noise engineering method. The ground vibrations caused by the SIP-method were measured and analyzed in each step. From the analysis results, quantitative ground vibration values and reliable vibration estimation equations were proposed. Furthermore, the ground vibrations caused by the SIP-method were compared with the ground vibrations caused by other methods presented by existing studies. Based on the vibration estimation equation with 50 % reliability, the ground vibration values by the SIP-method at the distance of 10~150 m corresponded to 17~57 % of the ground vibration values by the equation proposed by Attewell & Famer, and 14~96 % of the ground vibration values by the equation proposed by Prof. Park in his study using a diesel drop hammer. These results showed that the ground vibration reduction effect of the SIP-method was higher those of other general engineering methods. Finally, the permissible scope of work using the SIP-method which meets the domestic vibration standards was presented.

• International Journal of Railway
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• 제6권3호
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• pp.95-106
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• 2013

Earthborne vibrations are induced by construction operation such as pile driving, roadbed compaction, and blasting and also by transit activities such as truck and trains. The earthborne vibration creates the stress waves traveling outward from the source and can structurally damage nearby buildings and structures in the forms of direct damage to structure and damage due to dynamic settlement. The wave propagation characteristics depends on impact or vibration energy, distance from the source, and soil characteristics. The aim of this paper is to provide a comprehensive review on the mechanistic of earthborne vibration and the current practice of vibration control and mitigation measures. The paper describes the state of knowledge in the areas of: (1) mechanics of earthborne vibration, (2) damage mechanism by earthborne vibration, (3) calculation, prediction of ground vibration, (4) the criteria of vibration limits, (5) vibration mitigation measures and their performance, and (6) the current practice of vibration control and mitigation measures.

• 한국콘텐츠학회논문지
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• 제20권11호
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• pp.669-675
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• 2020

본 연구에서는 헬리컬파일의 지지력 특성 규명을 위하여 현장재하시험을 통하여 얻은 실측 지지력과 이론식에 의해 산정된 예측 지지력을 비교 분석하였다. 헬리컬파일은 중공형 축에 중공형 축보다 직경이 큰 하나 혹은 다수의 나선형 원판을 부착시킨 형상의 파일이다. 헬리컬파일은 굴삭기에 부착된 회전관입기를 사용하여 파일을 지반에 회전 관입시키기 때문에 항타와 굴착이 필요한 다른 말뚝에 비해 소음이 작고, 비교적 소형 장비로 시공이 가능하여 공간이 협소한 도심지에서도 시공이 용이하다. 최근 들어 헬리컬파일을 적용한 기초 공법의 설계와 시공이 많이 실시되고 있으나 헬리컬파일의 지지력에 관한 연구는 설계와 시공 사례에 비하여 아직 미진하다. 현장재하시험은 이음부, 헬리컬파일의 규격, 재하시험의 종류, 그라우팅 실시 여부를 변수로 총 10회 실시하였다. 이론식에 의한 말뚝의 예측 지지력은 Individual bearing method와 Cylindrical shear method을 통하여 산정하였다.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.245-253
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• 2017

The increasing lack of good quality soils allowing the development of roadway, motorway, or railway networks, as well as large scale industrial facilities, necessitates the use of reinforcement techniques. Their aim is the improvement of the global performance of compressible soils, both in terms of settlement reduction and increase of the load bearing capacity. Among the various available techniques, the improvement of soils by incorporating vertical stiff piles appears to be a particularly appropriate solution, since it is easy to implement and does not require any substitution of significant soft soil volumes. The technique consists in driving a group of regularly spaced piles through a soft soil layer down to an underlying competent substratum. The surface load being thus transferred to this substratum by means of those reinforcing piles, which illustrates the case of a piled embankment. The differential settlements at the base of the embankment between the soft soil and the stiff piles lead to an "arching effect" in the embankment due to shearing mechanisms. This effect, which can be accentuated by the use of large pile caps, allows partial load transfer onto the pile, as well as surface settlement reduction, thus ensuring that the surface structure works properly. A technique for producing rigid piles has been developed to achieve in a single operation a rigid circular pile associated with a cone shaped head reversed on the place of a rigid circular pile. This technique has been used with success in a pile-supported road near Bourgoin-Jallieu (France). In this article, a numerical study based on this real case is proposed to highlight the functioning mode of this new technique in the case of industrial slabs.