• Title/Summary/Keyword: load-settlement curves

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Analysis of Load-Settlement Curves in Driven and Embedded Piles (항타 및 매입말뚝의 하중-침하량 곡선의 분석)

  • 천병식;조천환
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.61-70
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    • 1997
  • Although the load -settlement curve characteristics of embedded piles are different from those of driven piles, for the determination of their allowable loads the same analysis method has been adopted without any considerations. According to the related domestic chi teria, the analysis methods of load-settlement curve have some conflicts among themselves and have several vague points in obtaining the allowable capacity from ultimate or yield capacity. In order to solve those problems, the relevant literatures were reviewed. And also the result of 106 pile load tests was analysed. Analysis result indicates that analysis met hods of the load-settlement curve based on single mathematical curve are not suitable for the general analysis method of load-settlement curves due to their various characteristics. As a result, the appropriate analysis methods and safety factors for the determination of allowable capacity of pile are suggested in this paper.

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Evaluation of Skin Friction Using Tensile Load Testing of CPR Piles (CPR 말뚝의 인발재하시험을 통한 주면마찰력 평가)

  • Ko, Chin-Surk;Kim, Jung-Han;Noh, Jeongdu;Kang, Seong-Seung
    • The Journal of Engineering Geology
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    • v.30 no.1
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    • pp.59-69
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    • 2020
  • Pull-out load tests were performed on a CPR (Compaction grouting compound Pile with Reinforce) test pile, with skin friction being evaluated by the yield load and allowable bearing capacity after analyzing load-displacement curves and load-settlement curves. Results of the CPR test piles analyzed from the load-displacement curves show that the yield load and allowable bearing capacity of the large-diameter CPR test pile were about 1.4 times larger than that of the small-diameter pile. Results of the load-settlement curves reveal that the allowable bearing capacity of the CPR test pile with diameter of D500 was 1.2~2.1 times greater than that of the pile with diameter of D400. However, the allowable bearing capacity calculated using Fuller's analysis differed substantially from that determined using the P (Pull-out load) - S (Settlement) and log P - log S curves. Therefore, calculation of the allowable bearing capacity using Fuller's analysis is shown to be inappropriate.

Load Sharing Analysis of Piled Rafts Based on Non-linear Load-Settlement Characteristics (Piled Raft 기초의 비선형 하중-침하 특성을 고려한 하중분담 해석)

  • Choi, Kyu-Jin;Park, Dong-Gyu;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.28 no.11
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    • pp.33-40
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    • 2012
  • The design of Piled Raft foundations considering the load sharing between raft and piles provides a more economical solution than the conventional design approach based on bearing capacity of piles only. Generally, numerical methods are used to analyze the behavior of Piled Rafts due to its complexity and load sharing ratio is also estimated by numerical methods about some limited cases under specific load level and soil conditions. In this study, a method to estimate the load sharing between the raft and piles was developed which is based on load-settlement characteristics of foundation elements. Normalized load-settlement curves of the raft and pile groups were derived individually, and the relationship between load sharing ratio and foundation settlement was proposed by using these curves. For each load-settlement curves, hyperbolic type was adopted in order to describe the non-linear behavior of foundations. Centrifuge test results were compared with the results from proposed method, and the trends of variation of load sharing ratio with settlement presented from both were similar.

Final Settlement Prediction Methods of Embankments on Soft Clay

  • Lee, Dal-Won;Lim, Seong-Hun
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42
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    • pp.68-77
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    • 2000
  • Analyses, in which load was regarded as instant load and gradual step load, respectively, were performed with data measured on a gradually loaded field, and the results were inspected to find the effect of load conditions, and the final settlements which were predicted by Hyperbolic, Tan's, Asaoka's, and Monden's methods were compared with each other. Settlement curves in which load was regarded as instant load and gradual step load being to coincide at twice the time of duration of embankment. On the ground installed vertical drain, from the results of Hyperbolic, Tan's, Asaoka's, Monden's, Curve fitting I, and Curve fitting II (simple, carrillo) methods it was concluded that Asaoka, Curve fitting I, and Curve fitting II methods are reliable for prediction final settlement with back analysis.

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A Comparative Study on Field Tests for Driven Pile in Static Load Tests (말뚝의 정재하시험을 통한 현장시험 결과 분석)

  • Chun, Byung-Sik;Youn, Hwan-Ho;Youn, Byung-Tae;Kim, Young-Hun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1117-1124
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    • 2008
  • In This paper, load-settlement curves that obtained from 11 sites were analyzed. At all tests, the load is applied until apparent failure is observed. The validity of the ultimate and yield load estimation method and load calculated from the settlement criterion was investigated through comparison with the measured data. The result indicated that B. Hansen 80% criterion and Stability Plot in ultimate loading decision law almost have been regared as same by comparing measured date and ultimate bearing capacity decided in depending yield loading decision law from 13% to 46% difference have taeyaeen came out when measured data and Davisson was compared, and S-log t from 5% to 41% log P-log S from 14% to 50% difference have been came out. When Settlement standard and measured data was compared difference had been came out about 3% in total settlement 0.1D criterion and from 12% to 35% difference had been came out in net settlement.

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Axial Load Capacity Prediction of Single Piles in Clay and Sand Layers Using Nonlinear Load Transfer Curves (비선형 하중전이법에 의한 점토 및 모래층에서 파일의 지지력 예측)

  • Kim, Hyeongjoo;Mission, Joseleo;Song, Youngsun;Ban, Jaehong;Baeg, Pilsoon
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.5
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    • pp.45-52
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    • 2008
  • The present study has extended OpenSees, which is an open-source software framework DOS program for developing applications to idealize geotechnical and structural problems, for the static analysis of axial load capacity and settlement of single piles in MS Windows environment. The Windows version of OpenSees as improved by this study has enhanced the DOS version from a general purpose software program to a special purpose program for driven and bored pile analysis with additional features of pre-processing and post-processing and a user friendly graphical interface. The method used in the load capacity analysis is the numerical methods based on load transfer functions combined with finite elements. The use of empirical nonlinear T-z and Q-z load transfer curves to model soil-pile interaction in skin friction and end bearing, respectively, has been shown to capture the nonlinear soil-pile response under settlement due to load. Validation studies have shown the static load capacity and settlement predictions implemented in this study are in fair agreement with reference data from the static loading tests.

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A Comparative Study on the Evaluation of Bearing Capacity for Driven Pile in Static Load Test (현장정재하시험 결과를 통한 타입말뚝 지지력 판정법 비교 연구)

  • Chun, Byung-Sik;Seo, Deok-Dong;Choi, Heon-Kil;Yoon, Hwan-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.677-686
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    • 2005
  • The allowable bearing capacity of a pile, the most important factor in stability estimation, is determined by applying safety factor to the ultimate load or yield load. There are several but contradictory methods available in current design codes to estimate the allowable bearing capacity and the safety factor. This paper analyzes load-settlement curves obtained from 19 static load tests measured from 11 sites. At all tests, the load is applied until apparent failure is observed. The validity of the ultimate and yield load estimation method and load caculated from the settlement criterion is investigated through comparison with the measured data. In addition, a new procedure to estimate allowable load and safety factor is proposed. Additional data from field static load tests, such as those incorporated in this study, are needed to more reliably apply the proposed method in design practice.

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