• 제목/요약/키워드: In-pile Data

검색결과 314건 처리시간 0.024초

사례 분석을 통한 복합말뚝 이음위치의 설계 기준식 개선 연구 (A Study for Improved Design Criteria of Composite Pile Joint Location based on Case Analysis)

  • 황의성
    • 한국지반환경공학회 논문집
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    • 제20권3호
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    • pp.21-30
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    • 2019
  • 복합말뚝(Composite Pile)이란, 수평력이 크게 작용하는 구간에는 강관말뚝, 작게 작용하는 구간에는 PHC말뚝을 특수한 연결 장치로 결합한 말뚝으로서 토목 구조물의 기초 재료로써 상용화되는 추세에 있다. 이러한 복합말뚝의 핵심은 강관말뚝과 PHC말뚝을 연결하는 연결 장치의 안정성과, 이음 위치를 산정하는 설계기준이라고 할 수 있는데 국내에서는 복합말뚝 이음부 위치에 대한 정확한 시방규정이 없어서, LH 설계처(한국토지주택공사, 2009)에서는 도로설계요령 제3권(한국도로공사, 2001)을 참고하여 작성한 "복합말뚝 설계적용 및 설계도서 표기 방안 검토"를 복합말뚝 설계의 기준으로 사용해 오고 있지만 복합말뚝의 단면변화라고 볼 수 없어 적용에 한계성을 가지고 있는 실정이다. 이에 따라 본 연구에서는 복합말뚝의 단면 변화부(강관말뚝과 PHC말뚝의 이음부) 위치에 대한 설계기준을 제안하고 이에 대한 안정성 및 경제성을 검토하고자 실험적인 방법과 해석적인 방법을 이용하여 연결장치에 대한 안정성을 검증하였으며, 국내 교량공사 교대 79개소에 시공된 복합말뚝 설계자료를 분석하여 말뚝 본체 및 이음부에 작용하는 응력, 휨모멘트, 변위 등의 경향성을 파악하였고, 개선식이 적용된 재설계 과정을 통해 이음부에서 발생한 응력들이 연결장치와 PHC말뚝의 허용응력 수치 내로 발생하는 것을 확인하였다. 결론적으로 사례분석을 통한 복합말뚝 이음위치의 설계 제안식은 복합말뚝을 설계함에 있어서 안정성과 경제성을 모두 고려한 개선된 설계기법임을 알 수 있었다.

Effect of soil condition on the coefficient of lateral earth pressure inside an open-ended pipe pile

  • Ko, Junyoung;Jeong, Sangseom;Seo, Hoyoung
    • Geomechanics and Engineering
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    • 제31권2호
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    • pp.209-222
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    • 2022
  • Finite element analyses using coupled Eulerian-Lagrangian technique are performed to investigate the effect of soil conditions on plugging of open-ended piles in sands. Results from numerical simulations are compared against the data from field load tests on three open-ended piles and show very good agreement. A parametric study focusing on determination of the coefficient of lateral earth pressure (K) in soil plug after pile driving are then performed for various soil densities, end-bearing conditions, and layering conditions. Results from the parametric study suggest that the K value in the soil plug - and hence the degree of soil plugging - increases with increasing soil densities. The analysis results further show that the K value within the soil plug can reach about 63 to 71% of the coefficient of passive earth pressure after pile driving. For layered soil profiles, the greater K values are achieved after pile driving when the denser soil layer is present near the pile base regardless of number of soil layers. This study provides comprehensive numerical and experimental data that can be used to develop advanced theory for analysis and design of open-ended pipe piles, especially for estimation of inner shaft resistance after pile driving.

검증용 정재하시험 자료를 이용한 항타강관말뚝의 신뢰성 평가 (Reliability Updates of Driven Piles Using Proof Pile Load Test Results)

  • 박재현;김동욱;곽기석;정문경;김준영;정충기
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 춘계 학술발표회
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    • pp.324-337
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    • 2010
  • For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

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지반-구조뭍간 상호작용을 고려한 암반에 근입된 현장타설말뚝의 거동 (The Behavior of the Cast-in-place Pile Socketed in Rock Considering Soil-Structure Interaction)

  • 최진오;권오성;김명모
    • 한국암반공학회:학술대회논문집
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    • 한국암반공학회 2000년도 암반공학문제의 수치해석(Numerical Analysis in Rock Engineering Problems)
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    • pp.211-222
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    • 2000
  • 대형 구조물 기초로 암반에 근입된 현장타설말뚝의 사용이 현저히 증가하고 있음에도 암반의 공학적 물성과 설계정수와의 관련이 명확히 정립되지 못한실정이다. 이에 본 연구에서는 암반근입말뚝의 거동 특성을 이론적으로 연구하고, 이를 수치적으로 모델링하기 위하여 지반-구조물 상호작용에 관련한 경계면 물성을 기존 연구 결과에 기초하여 합리적으로 산정하였다. 암반의 물성과 경계면 물성간의 관계를 이용하여 암반근입말뚝의 거동을 수치적으로 모사할 수 있으며 , 또한 현장 계측을 통해 얻은 말뚝의 하중전이 양상이 수치적으로 모사된 결과와 잘 일치함을 확인하였다.

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지반-구조물간 상호작용을 고려한 암반에 근입된 현장타설말뚝의 거동 (The Behavior of the Cast-in-place Pile Socketed in Rock Considering Soil-Structure Interaction)

  • 최진오;권오성;김명모
    • 터널과지하공간
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    • 제10권3호
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    • pp.457-468
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    • 2000
  • 대형 구조물 기초로 암반에 근입된 현장타설말뚝의 사용이 현저히 증가하고 있음에도 암반의 공학적 물성과 설계정수와의 관련이 명확히 정립되지 못한 실정이다. 이에 본 연구에서는 암반근입말뚝의 거동 특성을 이론적으로 연구하고, 이를 수치적으로 모델링하기 위하여 지반-구조물 상호작용에 관련한 경계면 물성을 기존 연구 결과에 기초하여 합리적으로 산정 하였다. 암반의 물성과 경계면 물성간의 관계를 이용하여 암반근입말뚝의 거동을 수치적으로 모사 할 수 있으며, 또한 현장 계측을 통해 얻은 말뚝의 하중전이 양상이 수치적으로 모사 된 결과와 잘 일치함을 확인하였다.

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Field test of the long-term settlement for the post-grouted pile in the deep-thick soft soil

  • Zou, Jin-Feng;Yang, Tao;Deng, Dong-ping
    • Geomechanics and Engineering
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    • 제19권2호
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    • pp.115-126
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    • 2019
  • The long-term settlement characteristics for the cast-in-place bored pile in the deep-thick soft soil are investigated by post-grouting field tests. Six cast-in-place bored engineering piles and three cast-in-place bored test piles are installed to study the long-term settlement characteristics. Three post-grouting methods (i.e., post-tip-grouting, post-side-grouting, and tip and side post-grouting) are designed and carried out by field tests. Results of the local test show that decreased settlements for the post-side-grouted pile, the post-tip-grouted pile and the tip and side post-grouted pile are 22.2%~25.8%, 30.10%~35.98% and 32.40%~35.50%, respectively, compared with non-grouted piles. The side friction resistance for non-grouted piles, post-side-grouted pile, post-tip-grouted pile and the tip and side post-grouted pile undertakes 89.6~91.3%, 94.6%, 92.4%~93.0%, 95.7% of the total loading, respectively. At last, the parameters back analysis method and numerical calculation are adopted to predict the long-term settlement characteristics of the cast-in-place bored pile in the deep-thick soft soil. Determined Bulk modulus (K) and a creep parameter (Ks) are used for the back analysis of the long-term settlement of the post-grouted pile. The settlement difference between the back analysis and the measurement data is about 1.11%-7.41%. Long-term settlement of the post-grouted piles are predicted by the back analysis method, and the predicted results show that the settlement of the post-grouted pile are less than 6 mm and will be stable in 30 days.

양방향재하시험을 통한 바렛말뚝의 하중-침하특성 연구 (Load-Displacement Characteristics Study of Barrette Pile by Bi-directional Loading Test)

  • 임대성;박성완;이상래
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.754-759
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    • 2008
  • Recently, the construction of buildings and large bridges has been increasing rapidly causing foundation structure growing larger then before, especially in the use of large size cast-in-place piles. Barrette Pile will usually be used at the site where diaphragm wall is the retaining wall to save time and cost in mobilization of equipments. This study uses bi-directional loading test data obtained from two different sites to observe the bearing capacity and displacement characteristics of barrette pile. Numerical analysis of the test is done by using commercial 3D computer program and the interface effect and capacity of the pile as well as displacement characteristics of the pile is verified.

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Barrette 파일을 이용한 지열시스템의 채열 성능 예측 및 경제성 분석에 관한 연구 (An Economic Analysis and Performance Prediction for a Ground Heat Pump System with Barrette Pile)

  • 채호병;남유진;박용부
    • 설비공학논문집
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    • 제25권11호
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    • pp.600-605
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    • 2013
  • Ground source heat pump systems (GSHP) can achieve higher performance of the system, by supplying more efficient heat source to the heat pump, than the conventional air-source heat pump system. But building clients and designers have hesitated to use GSHP systems, due to expensive initial cost, and uncertain economic feasibility. In order to reduce the initial cost, many researches have focused on the energy-pile system, using the structure of the building as a heat exchanger. Even though several experimental studies for the energy-pile system have been conducted, there was not enough data of quantitative evaluation with economic analysis and comprehensive analysis for the energy-pile. In this study, a prediction method has been developed for the energy pile system with barrette pile, using the ground heat transfer model and ground heat exchanger model. Moreover, a feasibility study for the energy pile system with barrette pile was conducted, by performance analysis and LCC assessment. As a result, it was found that the heat exchange rate of a barrette pile was 2.55 kW, and the payback period using LCC analysis was 8.8 years.

Study on Settlement Calculation of the Long-Short Pile Composite Foundation

  • XU, Xin;Kwag, Yunehyeong;Chun, Byungsik
    • 한국지반환경공학회 논문집
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    • 제14권7호
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    • pp.13-18
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    • 2013
  • As a new foundation treatment technology, long-short pile composite's design theory is still in primary phase, and there are no explicit settlement calculation methods in active codes. So it is necessary to study the working mechanism and the methods of settlement calculation. In this paper, the mechanics of long-short pile composite foundation are fully discussed. Meanwhile, based on the shear deformation method, the Mylonakis & Gazetas models about mutual action between two piles and the one between pile and soil are introduced, Considering the performance of cushion, the flexible factors of mutual actions are provided. Then the settlement calculation of long-short pile composite foundation which can consider the mutual actions between pile, soil and cap is deduced, and the correlated program is also developed. Finally, an engineering example is discussed with the method. A comparison shows that calculated results and measured data from a field test pile are in a good agreement, indicating that the presented approach is feasible and applicable in engineering practice.

건물 침하방지를 위한 Underpinning 사례연구 (A Case Study of Underpinning for Building Settlement Reduction)

  • 박병기;이인모
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1993년도 가을 학술발표회 논문집
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    • pp.57-62
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    • 1993
  • Settlements of maximum 23cm have occurred in and Apartment building consturcted on a fill layer with pile foundations. The main reason of the settlements was due to the negative skin friction applied to the pile, and settlement of adjacent ground since most pile tips are acted as a floating foundation founded on the stratum where the SPT N value was mostly less than 30. To underpin this building, the Jumbo Special Pile grouging was adopted, and instrumented data showed little differential settlement after the JSP underpinning.

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