• Title/Summary/Keyword: end bearing pile

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Experimental Study on the End Bearing Capacity of the Pile in a Group Pile (무리말뚝을 구성하는 개별말뚝의 선단지지력에 대한 실험연구)

  • Na, Yong Soo;Lee, Sang Duk
    • Journal of the Korean Geotechnical Society
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    • v.35 no.6
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    • pp.27-38
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    • 2019
  • Bearing capacity of a pile in homogeneous soil is the sum of end bearing and skin resistance, and the skin resistance is more prominent in sandy soil. Bearing capacity of a pile in pile groups especially in sandy ground should be designed under the consideration of the influence by the adjacent piles. In this study, the end bearing capacity of a pile in pile groups was experimentally investigated. For this purpose, piles were installed in sandy ground in a circular test box, and end bearing - settlement behavior of the pile was measured while the pile was loaded. As the results, end bearing - settlement relation curves of the piles showed a distinct limit value. Limit value of the end bearing was little affected by skin friction and pile diameter, and it became a constant value as pile penetrates deeper. End bearing was not affected by the adjacent piles in a group of piles, when their clearance was larger than the pile diameter.

Influence of Pile Cap On The Behaviors of End Bearing Pile Groups (말뚝캡이 선단지지 무리말뚝의 지지거동에 미치는 영향)

  • 최영석;이수형;정충기;김명모
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.245-252
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    • 2000
  • Model tests on free standing pile groups and piled footings with varying a pile spacing in two layered soils are carried out. The influence of pile cap on the behaviors of end bearing pile groups is analyzed by comparing the bearing behavior in piled footings with those in a single pile, a shallow footing(cap alone) and free standing pile groups. From the test results, it is found that the bearing characteristics of cap-soil-pile system are related with load levels and pile spacings. Before yield, the bearing resistance by cap is not fully mobilized, however, as the applied load increases, the bearing resistance of cap approaches to that of cap alone and settlement hardening occurs after yield due to the compaction caused by the contact pressure between cap and soil. By the cap-soil-pile interaction, shaft friction and point resistance of piles considerably increase with dependency of pile spacings. In two layered soil, the increasing effect of dilatancy in dense sandy soil adjacent to pile tips, increases the point resistance of pile.

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End shape and rotation effect on steel pipe pile installation effort and bearing resistance

  • Saleem, Muhammad A.;Malik, Adnan A.;Kuwano, Jiro
    • Geomechanics and Engineering
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    • v.23 no.6
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    • pp.523-533
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    • 2020
  • The current study focuses on the effect of the end shape of steel pipe piles on installation effort and bearing resistance using the pressing method of installation under dense ground conditions. The effect of pile rotation on the installation effort and bearing resistance is also investigated. The model steel piles with a flat end, cone end and cutting-edge end were used in this study. The test results indicated that cone end pile with the pressing method of installation required the least installation effort (load) and showed higher ultimate resistance than flat and cutting-edge end piles. However, pressing and rotation during cutting-edge end pile installation considerably reduces the installation effort (load and torque) if pile penetration in one rotation equal to the cutting-edge depth. Inclusion of rotation during pile installation reduces the ultimate bearing resistance. However, if penetration of the cutting-edge end pile equal to the cutting-edge depth in one rotation, the reduction in ultimate resistance can be minimized. In comparing the cone and cutting-edge end piles installed with pressing and rotation, the least installation effort is observed in the cutting-edge end pile installed with penetration rate equal to the cutting-edge depth per rotation.

Axial Load Transfer Behavior for Driven Open-ended End bearing Steel Pipe Pile (선단지지된 항타개단강관말뚝의 축하중전이거동)

  • 임태경;정성민;정창규;최용규
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.589-596
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    • 2002
  • In this study, static pile load tests with load transfer measurement were accomplished in the field. Yield pile capacity (or ultimate pile capacity) determined by load-settlement-time relationship was determined and axial load transfer behavior was analyzed. In the test for the four test piles were behaved as end bearing pile but ratios of skin friction to total pile capacity were 27%∼33%.

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A Study on the Measurement of End Bearing Capacity for Large Diameter Drilled Shaft Constructed in Fault Zone Using the Static Bi-directional End Leading Test (양방향 선단재하시험을 이용한 단층파쇄대에 시공된 대구경 현장타설말뚝의 선단지지력 측정 연구)

  • 정창규;정성민;황근배;최용규
    • Journal of the Korean Geotechnical Society
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    • v.20 no.5
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    • pp.135-143
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    • 2004
  • In the land section of marine bridge construction site, to confirm the end bearing of large diameter drilled shaft constructed in the fault zone which was discovered unexpectedly, the hi-directional end loading tests were performed. The objectives of this study are to confirm the end bearing of the pile constructed in fault zone and the increasing effect of end bearing after grouting the base ground beneath the pile toe. After grouting the pile base ground, the settlement of pile base decreased considerably and the pile base resistance increased more than twice.

P-S Characteristics for End-bearing Pile in Granular Material (사질토 지반에서 선단지지말뚝의 P-S 특성)

  • Lee Yong Joo
    • Journal of the Korean Geotechnical Society
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    • v.21 no.2
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    • pp.85-91
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    • 2005
  • This paper investigates P-S (load-settlement) relationship for the end-bearing Pile in granular material using the CRISP FE Program with the laboratory 2D model pile load test. In order to simulate the effect of end-bearing pile problem in the FEA, the author adopts several forms of slip element around the pile length and the pile tip. Through this study it was found that e degree of non-associated Plastic flow rule incoporated into the Mohr-Coulomb model for the end-bearing pile with the slip elements was a dominant factor in terms of numerical solution convergence. In contrast, the roller boundary used along the pile shaft showed a smooth convergence with respect to the degree of non-associated plastic flow rule.

Evaluation of Pile Bearing Capacity and Scale Effect Using Model Pile Test (모형실험을 통한 말뚝지지력의 평가 및 치수효과의 비교분석)

  • 이인모;이정학
    • Geotechnical Engineering
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    • v.9 no.4
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    • pp.37-44
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    • 1993
  • Model pile tests in calibration chamber are performed in order to study the two factors that the pile bearing capacity is significantly influenced by. Those factors are the critical depth concept and the scale effect caused by pile diameters. Firstly, the predicted values of end bearing capacity from the various static formulae were compared with the measured ones from model pile tests. Secondly, the critical depth concept and the scale effect were investigated by using two different soil conditions in a series of calibration chamber tests : the one is uniform sand : and the other is weathered granites overlayered by sand. Main results obtained from the model tests can be summarized as follows : (1) The end bearing capacity was increased with pile penetration depth up to penetration ratio of 7 to 8 when the cell pressure is high, and the critical depth was observed in the current chamber tests with uniform sand layer , (2) The predicted end bearing capacities were mostly lager than the measured, and it was found that the differences between the predicted and the measured values became smaller as the pile penetration ratio was increased : (3) The end bearing capacity of the small diameter pile in weathered granites layer was mostly less than that of the larger pile, while in uniform sand layer it was vice.

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A Case Study of Post-Grouted Drilled Shaft in Weathered Formation (풍화대소켓 대구경 현장타설말뚝의 선단보강그라우팅 사례)

  • Kwon, Oh-Sung;Lee, Jong-Sung;Jung, Sung-Min;Lee, Kyung-Jun;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.415-426
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    • 2010
  • Post-grouting for the drilled shaft is known to increase the end bearing capacity of pile 2~3 times higher by consolidating and reinforcing the disturbed ground containing slime around the pile end. However, the general design guideline for post-grouting has not been established yet in Korea. Especially in the domestic application, the post-grouting is employed just for repairing the pile with the unacceptable resistance rather than for increasing the design resistance of pile. Therefore, little is reported about the effect of post-grouting on the pile resistance itself. In this study, the effect of post-grouting on the resistance of drilled shafts installed in the weathered rock in Korea was estimated by performing the bi-directional load tests on the piles with and without the post-grouting. The test results presented that the initial slope of end bearing-base displacement curve in the pile with post-grouting was 4 times higher than that without post-grouting. At the acceptable settlement (1% of pile diameter), the end bearing capacities of piles with and without the post-grouting were estimated to be 12.0 MPa and 7.0 MPa, respectively, indicating that the post-grouting could increase the end bearing resistance of pile in weathered rock more than 70%.

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End Bearing Capacity of a Pile in Cohesionless Soils (사질토에 있어서 말뚝의 선단부 지지력)

  • 이명환
    • Proceedings of the Korean Geotechical Society Conference
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    • 1988.06c
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    • pp.71-123
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    • 1988
  • The aim of this paper is to examine the end bearing capacity of a pile in cohesionless soils. The ode of failure of soil due to pile installation is assumed from experimental observation of actual soil deformation. A new solution is proposed complying with the assumed mode of failure by employing the theory of cavity expansion. The effect of curvature of failure envelope is studied in relation to tile proposed solution. The influence of a curved failure envelope becomes larger with increasing degree of curvature and the level of confining stress. This effect in some cases or reduce the end bearing capacity by tore the 80 percent compared with that given by a straight failure envelope. For practical application of tile proposed solution, the method of determining the average volume change in the plastic zone is re-evaluated. The proposed solution is confirmed by comparing the theoretical values with experimental results obtained from model pile tests in a calibration chamber. The comparison shows that the proposed solution provides a reasonable prediction of end bearing capacity for both weak and strong grained soils.

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A Characteristics of Bearing Capacity by PG Pile on Waste Landfill (폐기물 매립지반에서 PG Pile의 지반지지력 특성)

  • 천병식;최춘식
    • Journal of the Korean Society for Railway
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    • v.3 no.4
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    • pp.213-218
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    • 2000
  • Waste landfill is so loose that it may cause the insufficient bearing capacity and the differential settlement. And so, characteristics and conditions of the ground should be considered in applications of ground improvement in waste landfill. In this paper, analysis of field tests as the static loading test and the bearing capacity test were performed. In result, PG(Pack Grouting) pile method is proved effective and economic, because it could bring about the increase of end bearing capacity, the prevention of differential settlement and increase of density by expansion of pile.

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