• Title/Summary/Keyword: sand compaction pile (SCP)

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Study on the Relationship of Strength Parameters with SCP Replacement and Mixture Ratio (모래다짐말뚝(SCP)의 치환율과 혼합율에 따른 강도정수의 상관성에 관한 연구)

  • 서주영;임종철;박이근
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.733-740
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    • 2003
  • When SCP (Sand Compaction Pile) is used in the improvement of soft ground, some problems like the difficulty of vertical construction and other construction difficulties due to the use of high pressure are encountered, There is a possibility that the strength parameters used in the design may be different with those obtained from the investigation of the quality variation with depth for the irregular, then the section may be not a sand pile but a combination of sand and clay. The mixture ratio concept is used, it is defined as the quantity of sand corresponding to the replacement ratio. Using this concept, the strength parameter relationship of the replacement and mixture ratio was determined. The use of these parameters in the design of SCP is most appropriate.

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An Experimental Study on the Behavior of Composite Ground Improved by SCP and GCP with Low Replacement Ratio (저치환율 SCP와 GCP로 개량된 복합지반의 거동에 관한 실험적 연구)

  • Kim, Byoung-Il;Yoo, Wan-Kyu;Kim, Young-Uk;Moon, In-Jong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.936-942
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    • 2013
  • This paper presents the results of laboratory tests conducted to investigate the effectiveness of applying methodology of a sand compaction(SCP) and a gravel compaction pile(GCP) on soft ground. The test conditions involved relatively low replacement ratios (=10, 20, and 30%) of a pile to unit cell at 1g (gravity acceleration) level. Results revealed that GCP significantly enhanced bearing capacity, settlement reduction, and consolidation rate compared with SCP.

Estimation of Ultimate Bearing Capacity of SCP and GCP Reinforced Clay for Laboratory Load Test Data (SCP 및 GCP 개량 점성토지반의 실내재하시험에 대한 극한지지력 산정 방법 개발)

  • Bong, Tae-Ho;Kim, Byoung-Il;Han, Jin-Tae
    • Journal of the Korean Geotechnical Society
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    • v.34 no.6
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    • pp.37-47
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    • 2018
  • In this study, 34 laboratory load test data were collected, and analyzed to propose the equations for predicting ultimate bearing capacity of sand compaction pile (SCP) and gravel compaction pile (GCP) reinforced clay. The collected data were compared with the ultimate bearing capacity estimated by existing theoretical equations, and the prediction accuracy of the existing theoretical equations was identified. Also, multiple regression analysis was performed to predict the ultimate bearing capacity, and the most efficient number and type of input variables were selected through error evaluation by leave-one-out cross validation. Finally, the multiple regression equations for estimating the ultimate bearing capacity of laboratory load test for SCP and GCP were proposed, and their performance was evaluated.

Two Dimensional Finite Element Analysis on the Composite Ground Improved by Sand Compaction Piles with Low Area Replacement Ratio (저치환율 SCP 복합지반의 2차원 유한요소 해석기법 개발과 적용)

  • Shin, Hyun-Young;Han, Sang-Jae;Kim, Soo-Sam;Kim, Jae-Kwon;Sym, Sung-Hyun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.394-401
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    • 2006
  • This study developed two dimensional finite element program(FE-SCP) for the analysis of a composite ground reinforced by sand compaction piles with a low area replacement ratio based on the Mohr-Coulomb elastic perfectly plastic constitutive model. Program FE-SCP give some conveniences to users such as automatic mesh generation according to the replacement ratio and the effective sand pile diameter in the post processor. Also, it contains optimum processor in calculation of In-situ stress equilibrium considering different coefficient of earth pressure between sand pile and surrounding clay. Estimated stress-strain behavior using FE-SCP and the measured one from a centrifuge test showed good agreement comparing to the result from a general finite element program.

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Mechanism on Bulb Formation of Compaction Pile Depending on Materials (재료에 따른 다짐말뚝 구근 형성 메커니즘)

  • Choi, Jeong Ho;Lee, Min Jy;Falcon, Sen Sven;Park, Seong Jin;Choo, Yun Wook;Kim, Il Gon;Kim, Byeong Kyu
    • Journal of the Korean Geotechnical Society
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    • v.38 no.7
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    • pp.25-37
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    • 2022
  • In this paper, a small-scale model testing system was developed using a series of small-scale model tests to analyze the mechanism of compaction pile formation and evaluate the quality of controlled grading aggregates proposed as an alternative material to the sand compaction pile (SCP) method and granular compaction pile (GCP). These are the most typical ground improvement methods in field practice, particularly for soft grounds. However, the SCP has faced difficulties due to the supply shortage of natural sand and the corresponding price surge of sand. The GCP is limited in marine soft grounds because of the failure occurring at the pile tip caused by excessive expansion of the deeper bulbs, leading to uneven bulb formation. The uniformity of compacted pile bulbs is critical to ensuring the bearing capacity and quality of the compaction pile. This study aims to evaluate the performance of the new material and controlled grading aggregates using small-scale model tests simulating field compaction process to investigate its potential application in comparison with SCP. The compaction piles are examined in four cases according to different materials used for compaction pile and clay strength. The compaction pile materials, which are made of sand and controlled grading aggregates, used in this study were compared to reveal the mechanism of the bulb creation. The experimental data confirm that the bulb formation quality of the traditional sand and the new material, controlled grading aggregates are comparable. The compaction pile made of controlled grading aggregates presents higher bearing capacity than that of marine sand.

Consolidation Behavior of SCP Improved Ground at Pusan New Port Part 1-1 (부산신항 1-1단계 SCP 개량지반 압밀 특성)

  • JUNG JONG-BUM;YANG SANG-YONG;BYUN JUN-GI
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.11a
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    • pp.51-56
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    • 2004
  • The sand compaction pile (SCP) method, which forms a composite ground by driving sand piles into clay deposit, is the most commonly used soil improvement techniques in many countries for more than 30 years. Installation of sand compaction piles reduces the amount of consolidation settlement and increases the bearing capacity of soft clay deposit. In this paper, field survey conducted to investigated the consolidation behavior of the composite ground improved by SCPs. It is suggested that the measured consolidation velocity is later than design theory, however measured consolidation settlement is higher than design theory.

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Experimental Study on Bearing Capacity of Ground Treated by Sand Compaction Piles (모래다짐말뚝(SCP) 시공지반의 지지력에 관한 실험적 연구)

  • 김병일;김영욱;이상익;최용성
    • Journal of the Korean Geotechnical Society
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    • v.20 no.4
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    • pp.39-47
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    • 2004
  • The SCP(sand compaction pile) method which is a vertical reinforcing technique for soft ground using a sand compaction pile has received increasing popularity in Korea. Currently, there are different methods to evaluate the bearing capacity of the reinforced ground by the SCP method. However, a method that can consider the effect of the replacement ratio on the bearing capacity is not yet available. This study investigated the effect of the replacement ratio on the bearing capacity of the reinforced ground by the SCP method. The study involved laboratory experiments which were conducted on a centrifuge facility. Test conditions included various ranges of replacement ratios (20, 30, and 40%), centrifuged consolidation, and loading. From the results of the study, a method which can evaluate the bearing capacity of the reinforced ground was proposed and verified using the weighted average of the replacement ratio.

The Characteristics of the Composite Ground with Sand Compaction Pile(SCP) using Large Soil Box (대형토조시험을 이용한 모래다짐말뚝이 적용된 복합지반의 침하 및 하중전이특성)

  • Kim, Oo-Seok;Park, Eon-Sang;Kim, Jae-Kwon;Kim, Soo-Sam
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.974-981
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    • 2005
  • Because general laboratory tests for sand compaction pile method including unit-cell test device have fixed outside diameter, as area replacement ratio increase, diameter of sand pile increase. These condition can bring about overestimation of stiffness of composite ground. In addition, existing large soil box which consist of bellows type loading plate can occur serious mistake in checking the amount of drained water because there are additional drainage along the inside wall in device. Overcoming these shortcoming, this paper developed modified large scale soil box consist of piston type load plate. In this study, using this device, series of modified large scale soil box tests were performed, and investigated the settlement and stress transportation characteristics with area replacement ratio in sand compaction pile method.

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Experimental Study on Stress Sharing Behavior of Composition Ground Improved by Sand Compaction Piles with Low Replacement Area Ratio (저치환율 모래다짐말뚝에 의한 복합지반의 응력분담거동에 대한 실험적 연구)

  • 유승경
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.253-261
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    • 2003
  • Mechanical behavior of composition pound improved by sand compaction pile (SCP) with low replacement area ratio could be more significantly affected by mechanical interaction between sand piles and clays than that of clay ground improved by SD or SCP with high replacement area ratio. It is essential to elucidate the mechanical interaction in the improved clay ground, in order to accurately estimate behavior in reducing settlement of the improved ground and increasing strength of clays. In this paper, through a series of model tests of composition ground improved by SCP with low replacement area ratio, each mechanical behaviors of sand piles and clays in the composition ground during consolidation was elucidated, together with stress sharing behavior between sand piles and clays.

A Case Study on the Application of Gravel Pile in Soft Ground (Gravel Pile에 의한 연약지반 개량 시험시공 사례연구)

  • 천병식;고용일;여유현;김백영;최현석
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.223-230
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    • 2000
  • Sand drain as a vertical drainage is widely used in soft ground improvement. Recently, sand, the principal source of sand drain, is running out. The in-situ tests were carried out to utilize gravel as a substitute for sand. In-situ tests area was divided into two areas by material used. One is Sand Drain(SD) and Sand Compaction Pile(SCP) area, the other is Gravel Drain(GD) and Gravel Compaction Pile(GCP) area. Both areas were monitored to obtain the information on settlement, pore water pressure and bearing capacity by measuring instruments for stage loading caused by embankment. The results of measurements were analyzed, The clogging effect was checked at various depth in gravel column after the test. According to the test results, the settlement was found to be smaller in gravel drain than in sand drain. The increase in bearing capacity by gravel pile explains the result. The clogging effect was not found in gravel column. It is assumed that gravel is relatively acceptable as a drainage material. Gravel is considered to be a better material than sand for bearing capacity, and it is found that bearing capacity is larger when gravel is used as a gravel compaction pile than as a gravel drain.

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