• Title/Summary/Keyword: 항타

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Consideration of Set-up Effect in Wave Equation Analysis of Pile Driving. (Set-up 효과를 반영한 타입말뚝의 파동이론해석)

  • 천병식;조천환
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.95-104
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    • 1999
  • The bearing capacity of piles driven in soils showing set-up tendency increases with time. Though WEAP is an excellent tool for evaluating the driveability of driven pile, it has some limitations to predict reliable bearing capacity of pile after driving. It is because the existing WEAP method cannot take into account time-dependent soil properties after driving. The set-up effect should be accounted for to obtain a reliable bearing capacity by the WEAP. Unfortunately, there are no sufficient methods to take the set-up effect into consideration in wave equation analysis. This paper suggests an alternative to consider time effect in wave equation analysis through statistical analysis of dynamic load test data both at the end of driving and in the beginning of restrike. It is shown that the suggested parameters(quake and damping) would be more reliable than the existing one for the wave equation analysis of driven piles.

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A Study on Marine Pile Construction Management by Real-Time Kinematic GPS Positioning (RTK-GPS 측량에 의한 해상파일 시공관리에 관한 연구)

  • 강길선
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.4
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    • pp.393-401
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    • 2003
  • Automatic control technologies for the marine pile driving provides accurate and rapid intruding into the planned positions of the pile with planned slope and direction, so that the construction maintenance and management are more efficient and the quality of the construction is more promising. Therefore, in this study, the application scheme of RTK GPS to the automatic control of the pile driving presented. It is expected that the presented scheme using the precise RTK GPS technique assures the efficient and economic 3D positioning accuracy for the precise marine construction management like the precise foundation of marine structures made of piles and the dredging work. It is found that the suggested scheme decrease 60% of the construction error compared with specifications reference because marine position accuracy is measured within 4cm in real time. In addition, the automatic position control system using GPS reduced the construction period and cost compared with existing methods about 30% and 35%, respectively.

Analysis of Bearing Capacity of Rock Socketed Pre-Bored Super Strength Piles Based on Dynamic Load Test Results (동재하시험을 통한 선단이 암반에 근입된 초고강도 매입 PHC 말뚝의 지지력 특성 분석)

  • Kim, Rakhyun;Kim, Dongwook
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.3
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    • pp.89-100
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    • 2019
  • The purpose of this study is to analyze the characteristics of bearing capacity of pre-bored super strength PHC (SSPHC) piles socketed in rocks based on dynamic load test results. Because the SSPHC piles have high compressive concrete strengths compared with those of regular high strength PHC piles, the allowable structural strengths of the SSPHC piles were increased. For optimal design of the super strength PHC piles, the geotechnical bearing capacity of the SSPHC piles should also increased to balance the increased allowable structural strength of the SSPHC piles. Current practices of pile installation apply the same amount of driving energy on both SSPHC and high strength PHC piles. As results of analyzing factors that influence bearing strength of SSPHC piles using dynamic load test, there was no relationship between SPT-N value at pile toe and end bearing capacity. But driving energy effects on end bearing capacity. In case of skin friction, driving energy had no effects. And reasonable method verifying design bearing strength is necessary because end bearing capacity is not considered sufficiently in restrike test results.

Applicability of CPT-based Toe Bearing Capacity of PHC Driven Piles (PHC 항타말뚝에 대한 CPT 선단 지지력 산정식의 적용성)

  • Le, Chi Hung;Chung, Sung-Gyo;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.25 no.12
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    • pp.107-118
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    • 2009
  • As CPT penetration tends to show a similar behavior to that of pile driving, a number of methods for estimating the toe bearing capacity of piles based on CPT data have been proposed. To evaluate the applicability of the methods in this country, a total of 172 dynamic load tests data on PHC piles and 82 CPT data at a site in the Nakdong River estuary were collected. A specific four-step procedure was adopted for the selection of the reliable data, and statistical techniques were then applied to the analysis of the applicability. The results indicated that among a total of 10 CPT-based methods applied, the best one is the Aoki method (1975), followed by the LCPC (1982), ICP (2005) methods and others.

Design Efficiency Improvement Method Research for High Strength Steel Pipe Pile at Gwangyang Area (광양지역 고강도 강관 항타말뚝의 설계효율 향상 방안 연구)

  • La, SeungMin;Yoo, Hankyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6C
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    • pp.231-240
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    • 2011
  • Various pile load tests were carried out at Gwangyang district for 10 different piles in order to analyze the characteristcs of steel pile using high strength steel and high driving energy. Pile drivability results showed that PHC piles needed highest total blow count even with the shortest pile length and high strength steel pipe piles showed smallest total blow count eventhough driven to a more hard ground condition with longer pile length. Pile dynamic analysis results showed that for PHC pile and general steel pipe pile the allowable pile design load was decided by the allowable material strength but for high strength steel pipe pile the design load can be decided according to the ground bearing capacity. Static load test and load transfer test results showed that the pile design efficiency could be improved over 80% allowing lesser number of piles necessary for a more economical solution. Set-up effects was analyzed and regression equation for the site ground condition was derived. Bearing capacity was checked with widely used design equation and the limitation of current design method and future technology development on this subject is dicussed in this paper.

인공진동의 크기가 콘크리트의 강도와 물성에 미치는 영향

  • 정동호;이상은;임한욱
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 1994.03a
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    • pp.75-80
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    • 1994
  • 지반의 진동은 크게 지진과 같은 자연적인 진동과 발파, 항타(piling) 및 중장비의 가동 등에 따른 건설진동 등 인공진동으로 나눌 수 있는데 이들 지반진동은 지상 구조물의 안전도에 큰 영향을 미친다. 특히 양생(養生)중인 모르타르 및 콘크리트의 강도 및 물리적 성질에 큰 영향을 미치기 때문에 선진국에서는 엄격히 제한하고 있다. (중략)

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The Design of Parameters to Improve Actuating Performance in High Frequency Vibro-Hammer(HFVH) and the Study of Characteristic Propagation and Attenuation of Piling Vibration (초고주파 진동항타기의 구동 성능향상을 위한 파라미터 설계 및 항타진동의 전달과 감쇠특성에 관한 연구)

  • Jang, Tae-In;Park, Joon-Hyuk;Baek, Yoon-Su;Kim, Sung-Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.6
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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.

Effect of Embedment Ratio and Loading Rate on Uplift Adhesion Factor of Concrete Driven Pile (근입비와 인발속도가 콘크리트 항타말뚝의 인발부착계수에 미치는 영향)

  • Kim Jong-In;Park Jeong-Jun;Shin Eun-Chul
    • Journal of the Korean Society for Railway
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    • v.8 no.4
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    • pp.367-371
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    • 2005
  • Pile foundations are utilized when soil is so weak that shallow foundations are not suitable or point load is concentrated in small area. Such soil can be formed by the land reclamation works which have extensively been executed along the coastal line of southern and western parts of the Korean Peninsula. The working load at pile is sometimes subjected to not only compression load but also lateral load sad uplift forces. But in most of the practice design, uplift capacity of pile foundation is not considered and estimation of uplift capacity is presumed on the compression skin friction. This study was carried out to determine that the effect of embedment ratio and loading rate on uplift adhesion factor of concrete pile driven in clay. Based on the test results, the critical embedment ratio is about 9. Adhesion factor is constant under the critical embedment ratio, and decreasing over the critical embedment ratio. Also, adhesion factor is increased with the loading rate is increased.

Effect of Pile Construction on Lateral Behavior of Single Rigid Pile in Sand (사질토 지반에서 단일 강성말뚝의 수평거동에 대한 시공방법의 영향)

  • 김병탁;김영수;서인식
    • Journal of the Korean Geotechnical Society
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    • v.15 no.6
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    • pp.29-44
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    • 1999
  • This paper shows the results of model tests on the lateral behavior of single rigid pile, which was constructed by driving, in homogeneous and non-homogeneous (two layered) NakDong River sands. The purpose of the present paper is to investigate the effect of ratio of lower layer thickness to embedded pile length, relative density of sand and pile construction conditions (Driven & Embedded piles) on the characteristics of lateral behavior of single pile. These effects can be quantified only by the results of model tests. As a model result, the lateral behavior depends upon the pile construction condition in loose-density soil more than in high-density soil. If the pile construction depends upon driving construction, the decrease of deflection remarkably increases for both loose homogeneous sand and non-homogeneous soil$(E_{h1}/E_{h2}/=0.18)$ with high thickness of upper layer but the decrease of maximum bending moment shows the opposite result to the decrease of deflection. And, with respect to deflection, it was found that the deflection ratio $(y_{Driven}y_{Embedded})$ of embedded to driven piles has the ranges of 0.65 - 0.88 $(D_r=90%)$0.38 - 0.65 $(D_r=61.8%)$ for each relative density of homogeneous soil and the range of 0.6 - 0.88 for non-homogeneous soil. Also, in this study, the experimental equation for the effects of drop height (DH) and H/L on the ratios of $y_D/y_E\; and MBM_D/MBM_ E$ is suggested from model tests.

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