• Title/Summary/Keyword: Settlement behavior

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Prediction of Settlement for the Highly Plastic and Silty Soft Ground Contained of the Organic Deposits (유기질층을 포함한 고소성 실트질 연약지반의 침하 예측)

  • Yoo, Nam-Jae;Kim, Kyum;Yoo, Chang-Sun
    • Journal of Industrial Technology
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    • v.31 no.B
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    • pp.91-98
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    • 2011
  • In this thesis, from the results of settlement measurement performed at the site where embankment earthwork was carried out on the ground consisting of highly plastic and silty soft soils interlayered with organic deposits, various methods of predicting the embankment settlement such as Hoshino's method, Asaoka's method, hyperbolic method, ${\sqrt{s}}$ method and Monden's method were used to investigate their applicability and the inverse method of finding the soil parameter related to consolidation was used to predict the consolidation behavior in the future. It was confirmed that reliable prediction of consolidation behavior under various conditions could be done to estimate soil parameter related to consolidation such as the consolidation index and consolidation coefficient by the inverse method of comparing the measured settlement with the predicted value by the settlement prediction methods.

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Settlement Behavior Characteristics of CFRD in Construction Period - Case of Daegok Dam - (콘크리트 표면 차수벽형 석괴댐의 축조 중 침하거동 특성 - 대곡댐을 중심으로 -)

  • Park Han-Gyu;Kim Yong-Seong;Seo Min-Woo;Lim Heui-Dae
    • Journal of the Korean Geotechnical Society
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    • v.21 no.7
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    • pp.91-105
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    • 2005
  • In this study, the deformation behavior of Daegok dam during the construction was analyzed based on the measurement data and a comparative analysis with foreign CFRD measurements was performed. From measuring settlements of Daegok dam with depth, overall behavior was evaluated to be consistent with measured data of other CFRD dams. In addition, construction modulus, void ratio and shape factor were also evaluated to be major factors in predicting the settlement behavior during construction of CFRD-typed dam from measured data of 38 CFRD-typed dams, and the maximum internal settlement is proportional to the void ratio. From the relationship between the maximum internal settlement and the height of a dam, 26 dams were assessed to have its relative modulus ranging between 0.001 and 0.01. In case of general CFRD, the average modulus of maximum internal settlement to the height of a dam is estimated to be 0.005. In case of a low void ratio, the construction modulus was high with its shape factor below 4. On the other hand, in case of a high void ratio, the relative settlement rate was high with its shape factor more than 4.

Load-Settlement Characteristics of Concrete TOP-BASE Foundation on Soft Ground (팽이기초공법(Top-Base Method)의 하중-침하량 분석)

  • Kim, Jae-Young;Jeong, Sang-Seom;Lee, Jae-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.210-221
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    • 2009
  • A new foundation type which is called Top-Base method has been used frequently in engineering practices in Korea. In this study, the settlement behavior of concrete Top-Base foundation on soft ground is investigated since the consolidation settlement of the embedding depth and the effect of footing dimensions are not included in current Korean criterion (2007). To obtain detailed information, the model tests of the Top-Base foundation are performed using the PLAXIS 3D finite element analysis. It is shown that in-situ measurements and finite element analysis of the behavior of foundations indicate that consolidation settlement is reduced up and bearing capacity of the foundation increases up to 50%~100%, compared to the primary non-treated ground. Based on this study, it is found that the Top-Base foundation prevents the lateral deformation of soft ground and reduces its negative dilatancy to the surface settlement, and that the foundation creates rather uniform stress distribution under it to increase its bearing capacity. It is also found that the total settlement of Top-Base foundation was highly dependent on the consolidation settlement and footing configurations.

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Cracking Behavior of Prestressed Concrete Cylinder Pipe (프리스트레스트 콘크리트 실린더의 균열거동 연구)

  • Chung, Chul-Hun;Kim, Jong-Suk;Song, Na-Young
    • Journal of the Korean Society of Safety
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    • v.23 no.6
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    • pp.122-130
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    • 2008
  • The cracking behavior of prestressed concrete members is important for the rational evaluation of PCC pipes. However, the test data on the cracking behavior of PCC pipes are very limited. The purpose of the present study is to investigate the cracking behavior of PCC pipes under different settlement conditions. In this paper, experimental test on the full scale model of PCC pipe was conducted and observed in order to study cracking load in PCC pipes. Based test and FEM analysis results, this paper also presents the cracking load prediction in PCC pipe. Based on the numerical analysis results performed in this research, the cracking behaviors of PCC pipe with the variation of the settlement conditions were evaluated.

A Study on Behavior of Elastic Settlement of Coastal Structure on Sandy Ground (모래층 지반 안벽구조물의 탄성침하거동 연구)

  • Yoo, Nam-Jae;Jun, Sang-Hyun;Jeon, Jin-Yong
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.201-208
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    • 2007
  • This paper is research results of investigating the elastic settlement behavior of the coastal caisson structure built on the sandy deposit by comparing results of centrifuge model experiments and those of existing methods of estimating elastic settlement. Basic soil property tests such as specific gravity test, grain size distribution test and organic content test with disturbed soil sampled from the site were carried out. The centrifuge experiment of model satisfying the required design criteria was performed under 50 of artificial accelerated gravitational force condition. The Centrifuge model experimental results were compared and analyzed with the current methods of estimating settlement based on the elastic modulus obtained from the results of odeometer tests and empirical methods from literature reviews.

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Residual Settlement Behavior in Soft Ground Improved by PBD during Operating Facilities (PBD공법이 적용된 연약지반에서 운용 중인 시설물의 잔류침하거동)

  • Kang, Gichun;Kim, Taehyung;Jeong, Choonggi
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.8
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    • pp.13-21
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    • 2014
  • The Plastic Board Drain is used to improve soft soils deposited in container terminal area at a port. This paper describes settlement behavior of soft ground in this area from PBD installation to the time of operating facilities. Previous researches focused on soil improvement effect of PBD, that is, the settlement occurred during ground improvement period. The residual settlement occurred during operating the facility is very important from the maintenance and management point of view. However, the study of this residual settlement has been rarely conducted. In this study, by analyzing the measured settlement data obtained from the container terminal area at the port, it was verified that the residual settlement induced during operating facilities occurred in a layer with PBD improvement. In addition, by comparison the settlement predicted by a numerical analysis with the settlement measured in the field, it was confirmed that the actual settlement is in the range of predicted settlement.

Development of Analytical Method of Piled-Raft Foundation Considering Nonlinear Behavior of Pile (말뚝의 비선형거동이 고려된 전면지지 말뚝기초 해석기법의 개발)

  • Park, Hyun-Il
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.17-24
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    • 2008
  • In this study, two-dimensional finite element method has been developed to simply consider the nonlinear load-settlement behavior of piled raft foundation subjected to vertical loads. The raft is modeled as the plate finite element based on Mindline's theory and the pile is modeled as the proposed simple pile model that is easy to consider the complex nonlinear load-settlement behavior between pile and soil. The developed numerical method has been compared with the settlement data of lab-scaled experiment and numerical solutions to verify that the developed numerical method shows satisfactory prediction for the nonlinear load-settlement of piled raft foundation.

An Experimental Study of Settlement Behavior of Artificial Reef according to Reinforcement Characteristics (해저 연약지반 보강 조건에 따른 인공어초 침하 거동에 대한 실험적 연구)

  • Yun, Dae-Ho;Kim, Yun-Tae
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.53-61
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    • 2017
  • Seabed settlement and erosion sometimes occurr when a artificial reef is installed in soft seabed. Therefore, this study carried out CBR test and water tank settlement test to investigate settlement behavior of artificial reef according to reinforcement characteristics such as reinforced types and reinforced area. Soil types of ground are sand, silt and clay deposits. Three reinforced types were prepared: unreinforced, geogrid and hybrid bamboo mat(HBM) with different reinforced area. Laboratory test results indicated that reinforced artificial reef improved bearing capacity of ground and reduced settlement as reinforced area increased. Especially, reinforced HBM provided more bearing capacity and less settlement than reinforced geogrid.

Case history in prediction of consolidation settlement and monitoring (준설매립 초연약지반의 압밀침하 거동 및 계측 사례)

  • Jeon, Je-Sung;Lee, Jong-Wook;Im, Eun-Sang;Kim, Jae-Hong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1712-1716
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    • 2008
  • Performance of ground improvement project using prefabricated vertical drains of condition, in which approximately 10m dredged fill overlies original soft foundation layer in the coastal area has been conducted. From field monitoring results, excessive ground settlement compared to predicted settlement in design stage developed during the following one year. In order to predict the final consolidation behavior, recalculation of consolidation settlements and back analysis using observed settlements were conducted. Field monitoring results of surface settlements were evaluated, and then corrected because large shear deformation was occurred by construction events in the early stages of consolidation. To predict the consolidation behavior, material functions and in-situ conditions from laboratory consolidation test were re-analyzed. Using these results, height of additional embankment is estimated to satisfy residual settlement limit and maintain an adequate ground elevation. The recalculated time-settlement curve has been compared to field monitoring results after additional surcharge was applied.

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Prediction of Settlement Based on Field Monitoring Data under Preloading Improvement with Ramp Loading

  • Woo, Sang-Inn;Yune, Chan-Young;Chung, Choong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.436-452
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    • 2008
  • In this study, the settlement prediction method based on field monitoring data under preloading improvement with ramp loading is developed. Settlement behavior can be predicted with field monitored settlement throughout the entire preloading process including ramp loading followed by constant loading. The developed method is verified by comparing its predicted results with results from physical model tests and field monitoring data.

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