• Title/Summary/Keyword: Small-scale field model pile test

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The Analysis of Skin Friction on Small-scale Prebored and Precast Piles Considering Cement Milk Influence (시멘트풀의 영향을 고려한 축소모형 매입말뚝의 거동분석)

  • Park, Jong-Jeon;Jung, Gyung-Ja;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.33 no.1
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    • pp.5-15
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    • 2017
  • Skin friction may be one of the most critical factors in designing the prebored and precast pile. Special attention was given to the interface behavior of cement milk-surrounding soil during the installation of prebored and precast pile. Small-scale field model pile test was conducted for the case of single pile. The size and geometry of the small-scale field model piles were designed with pile length 1.3m, boring diameter 0.067 m. Quick maintain-load test was conducted for the cases of boring diameter 150, 125, 90, 86, 74 mm and water-cement ratio 90, 70, 60%. It was shown that the bearing capacity of the pile increased as the cement-water ratio and cement milk thickness increased. Considering the scale effect between the small-scale model test and the actual construction site, it was found that cement milk thickness of 0.1~0.4D (50~200 mm) was reasonable for the stability of the structure. Also, the proper cement paste water / cement ratio was about 70% when considering the results of this study and quality control.

A Study on the p-y Curves by Small-Scale Model Tests (모형실험을 통한 말뚝의 p-y 곡선에 관한 연구)

  • Kim, Tae-Sik;Jeong, Sang-Seom;Kim, Young-Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1C
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    • pp.41-51
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    • 2008
  • The load distribution and deformation of single piles which is embedded in Jumunjin sand and Kimhae clay are investigated, based on small scale model tests. Special attention is given to the consideration of flexural rigidity in laterally loaded piles. To consider the flexural rigidity of the pile, tests are performed with the aluminium piles of three different length under different relative densities and undrained shear strength. The test results indicate that the initial slope from the results of tests is proportional to the depth and pile-soil rigidity in both soils. But the increasing rate of the initial slope in the clay is less than in the sand. In addition, the soil resistance is more related to the depth and soil condition than the pile rigidity. Base on the test results, an empirical formula is proposed, which is good agreement with previously published small scale model test and field lateral load test.

Bearing Capacity Study for Small-Scale Testing of Rotary Pile with Helix Plate (축소모형 로타리 파일의 나선날개에 따른 지지성능에 관한 연구)

  • Shin, Eun-Chul;Kim, Kyeong-Sig;Moon, Hyeong-Rok
    • Journal of the Korean Geosynthetics Society
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    • v.15 no.1
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    • pp.37-46
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    • 2016
  • Rotary pile consists a single or multiple helix plate and it is installed into the ground using the rotation of the helix plate. Rotary pile in soft ground is able to be supported by pile shaft and helix plate. When the pile is installed into hard layer relatively, the end bearing capacity is possible to be increased by the lower helix plate. In this paper, small-size rotary piles were manufactured with using steel pipe which is reduced to 1/5 size of the rotary pile on the construction field. Pile load test was carried out on the foundation soil which was formed by weathered soft soil. The bearing capacity of small-scale piles depends on the number of helix plate, the length of plate diameter, and an interval of plates, respectively. The bearing capacity of pile increases about 40% with 3 helix plate and it is also confirmed that the bearing capacity is improved about 10% as the increment of plate interval.

Evaluation of Point Bearing Capacity using Field Model Pile Test (현장 축소모형 말뚝 시험을 이용한 선단지지력 예측)

  • Lee, Chang-Ho;Lee, Woo-Jin;Jeong, Hun-Jun;Han, Shin-In
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.3
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    • pp.47-54
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    • 2005
  • In many practical cases, design methods of pile have been used mainly semi empirical bearing capacity equations. It can be done that confirmation of pile bearing capacities through using of dynamic and static tests during constructing or after constructions. If a prediction of layered point pile bearing capacity could be done through simple tests during field investigation, it could be done that more reliable design of pile than a prediction of using semi empirical equations or static formulations. This paper suggests a method to estimated point bearing capacity during in-situ investigation by using the dynamic rod model pile and verifies the point bearing capacity compare with results of static pile load tests. From test results, the unit ultimate point bearing capacities are relatively similar through a dynamic rod model pile tests and static pile load tests. The unit ultimate point bearing capacity by using N value is shown about 50 % value of measured unit ultimate point bearing capacity from field test result and the prediction of the unit ultimate point bearing capacity by using N value is shown very conservative, illogical and uneconomical pile designs.

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Evaluation of the q-w Curve on Rock-Socketed Drilled Shafts by Triaxial Compression Tests (삼축압축시험을 통한 암반에 근입된 현장타설말뚝의 선단 하중전이곡선 산정)

  • Kim, Tae-Hyung;Kim, Yong-Min;Jeong, Sang-Seom
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.455-465
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    • 2008
  • In this study, the load distribution and deformation of rock-socketed drilled shafts subjected to axial load are investigated based on small scale model tests. In order to analyze the effects of major influencing factors of end bearing capacity, Hoek-cell triaxial tests were performed. From the test results, it was found that the initial slope of end bearing load transfer (q-w) curve was highly dependent on rock mass modulus and pile diameter, while the ultimate unit toe resistance ($q_{max}$) was influenced by rock mass modulus and the spacing of discontinuities. End bearing load transfer function of drilled shafts socketed in rock was proposed based on the Hoek-cell triaxial test results and the field loading tests which were performed on granite and gneiss in South Korea. Through the comparison with pile load tests, it is found that the load-transfer curve by the present study is in good agreement with the general trend observed by field loading tests, and thus represents a significant improvement in the prediction of load transfer of drilled shaft.

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Development of 500kW Tidal Current Energy Converter and Uldolmok Field Test (500kW 조류력 발전장치 개발 및 울돌목 실증시험)

  • Sim, Wooseung;Choe, Ickhung;Lee, Kyuchan;Kim, Haiwook;Bae, Jonggug;Min, Kehsik
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.159.2-159.2
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    • 2011
  • Hyundai Heavy Industries has developed a tidal current energy converter utilizing the accumulated technology as the world largest constructor for ship and offshore structures. The model has two sets of turbines in both ends in order to utilize the bi-directional current flows in flood and ebb tide. The torque produced by turbine in tidal current is directly delivered to generator along the horizontal axis, in which the turbine, gear, generator, gear and turbine are connected successively. The manufactured model for field test has the turbine diameter of 5 meters to produce the maximum power of 500kW at maximum current speed of 5m/s. The technical verification of tidal power converter was performed by means of small scale model test in towing tank as well as field test at the Strait of Uldolmok located in Jindo of Jeollanamdo province. Field test was performed by mounting the tidal current converter on the SEP(Self Elevating Platform) which could lower the 4 vertical legs on the seabed and could elevate platform over the water surface using the hydraulic power for itself. The field test performed for a month shows that power output is similar or larger compared with the expected one in design stage. This paper presents the development of tidal current energy converter and real sea field test by Hyundai Heavy Industries. This project has finished successfully and provided the technical advance toward commercial services for tidal current power generation in the south-west region in Korea.

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