• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.617-627
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• 2021

In this study, a numerical analysis using a three-dimensional numerical simulation was performed to assess the applicability of foundation reinforcing method using load transfer apparatus which can be used in the remodeling of deteriorated structures. The numerical model was validated through comparison with the real scale experimental results, and then a parametric study was performed to investigate the effect of friction coefficient of load transfer apparatus and axial stiffness of pile on the performance of foundation reinforcing method. It was confirmed that the foundation reinforcing method considered in this study can efficiently control the load applied to an existing foundation.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.5-15
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• 2015

The GCP (Granular Compaction Pile) for the improvement objective of soft ground has been frequently studied. However, these studies were the results deduced on the basis of the numerical analysis and the laboratory model tests, and there was no study method to apply the effects of the bulging failure of a flexible pile. In this study, the sensitivity of the load-settlement curves of the uniform and the tapered GCP dependant on the geotechnical parameters estimated from N value of standard penetration test (SPT) was analyzed. It was estimated reasonably that, in the very soft clay soil (N=3 or less), elastic modulus was 700~2000 kPa and Poisson's ratio was 0.40~0.48.

• Geotechnical Engineering
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• v.12 no.6
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• pp.5-20
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• 1996

This paper presents results from a series of model tests on laterally loaded single piles with both free-head and free-tip conditions. Model tests, using a centrifuge apparatus (middie size, Mark II in 7.1.7.) were carried out in sand based on the variation of different gravity acceleration and flexural stiffness of the pile and relative density of the soil. The aims of this study are to estimate the effect of gravity acceleratioil, flexordis stiffness, and relative density on the behavior of the pile embedded in Toyoura sand and to evaluate the applicability of a family of the p-y curves which was presented by several reseachers(Mur chison & O'Neill, neese et n., scott, Det worske veritas, nondner). The Program is deviloped by using p-y curves, and it can be used for the calculation of the displacement distri bution, bending moment distribution, and soil reaction distribution. By comparing meas ured responses with predicted one it is shown that the results of the p-y curve equation presented by Murchison & O'Neill and Kondner agreed with the general trend observed by the centrifuge tests much better than the numerical solutions predicted by the other sets of p -y curves.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.87-97
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• 2020

Recently, interest in Tie-cell wave-dissipating blocks that can compensate for the disadvantages of block-type breakwaters and provide economically effective design is increasing. Tie-cell wave-dissipating block has high activity resistance due to its structure in which each block is held together by a pile. In this study, through the laboratory model experiments, it was possible to confirm the increase in lateral resistance of the Tie-cell wave-dissipating blocks due to the penetration of the piles. The lateral resistance of the piles appeared almost constant regardless of the overburden load of the blocks. The lateral resistance shared by the piles changed depending on the increase or decrease in the lateral resistance of the friction between blocks. In the experiment in which two piles were penetrated, the overall lateral resistance was larger than the case a single pile was used, but the resistance behavior of the piles was different.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1011-1016
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• 2009

In this study, to performed laboratory model tests in order to verify on load transfer condition of drilled shaft under lateral loading. To conducted model test on polystyle drilled shaft under multi layer ground conditions. In model test, to measured the strain of drilled shaft and displacement under later loading. In order to verify on model test results, to conduct the numerical analysis.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.5-13
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• 2000

모래지반의 상대밀도, 말뚝의 시공방법, 일정근입깊이에 따른 소요향타 에너지 그리고 지하수 조건에 따라 말뚝의 지지력과 하중전이를 연구하기 위하여 강관말뚝을 이용한 모형실험을 수행하였다. 매입말뚝은 말뚝을 미리 설치한후에 지반성형을 실시하였고, 타입말뚝은 매입말뚝과 같은 깊이까지 항타높이를 5, 10, 15cm로 달리하여 말뚝을 관입하였다. 그 뒤 정적하중을 단계적으로 가하여 하중-침하 곡선에 의한 모형 말뚝의 지지력과ㅏ 말뚝내의 등간격으로 설치된 변형 게이지를 이용하여 타입말뚝 의 하중전이에 대해 살펴보았다. 타입말뚝의 하중전이시험에서는 항타 전과 항타 후 말뚝내 하중전의 소효항타 에너지에 따른 변화를 관찰하였다. 매입말뚝의 시험결과는 현재 가장 많이 사용하고 있는 대표적인 정적 지지력 공식들에 의하여 계산되어진 값들과 비교 분석하였다. 그 결과 상대밀도가 작은 느슨한모래지반에서는 Vesic 공식이 그리고 상대밀도가 큰 조밀한 모래지반에서는 Hanbu 공식이 가장 근접한 평가를 나타내었다. 하중전이시험에 의한 항타시 잔류응력은 모든 경우에서 지표면과 선단부위에서 아주 큰 잔류응력이 나타났고. 말뚝의 선단 지지력비는 상대밀도에 비례하게 증가하였다.

• Wind and Structures
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• v.26 no.6
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• pp.343-354
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• 2018

A realistic FEM structural model is developed to predict the behavior, load transfer, force distribution and performance of a riverine platform under earthquake and environmental loads. The interaction between the transfer plate and the piles supporting the platform is investigated. Transfer plate structures have the ability to redistribute the loads from the superstructure above to piles group below, to provide safe transits of loads to piles group and thus to the soil, without failure of soil or structural elements. The distribution of piles affects the distribution of stress on both soil and platform. A materially nonlinear earthquake response spectrum analysis was performed on this riverine platform subjected to earthquake and environmental loads. A fixed connection between the piles and the platform is better in the design of the piles and the prospect of piles collapse is low while a hinged connection makes the prospect of damage high because of the larger displacements. A fixed connection between the piles and the platform is the most demanding case in the design of the platform slab (transfer plate) because of the high stress values developed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.133-144
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• 2009

Incheon Bridge, 18.4 km long sea-crossing bridge, will be opened to the traffic in October 2009 and this will be the new landmark of the gearing up north-east Asia as well as the largest & longest bridge of Korea. Incheon Bridge is the integrated set of several special featured bridges including a magnificent cable-stayed girder bridge which has a main span of 800 m width to cross the navigation channel in and out of the Port of Incheon. Incheon Bridge is making an epoch of long-span bridge designs thanks to the fully application of the AASHTO LRFD (load & resistance factor design) to both the superstructures and the substructures. A state-of-the-art of the geotechnologies which were applied to the Incheon Bridge construction project is introduced. The most Large-diameter drilled shafts were penetrated into the bedrock to support the colossal superstructures. The bearing capacity and deformational characteristics of the foundations were verified through the world's largest static pile load test. 8 full-scale pilot piles were tested in both offshore site and onshore area prior to the commencement of constructions. Compressible load beyond 30,000 tonf pressed a single 3 m diameter foundation pile by means of bi-directional loading method including the Osterberg cell techniques. Detailed site investigation to characterize the subsurface properties had been carried out. Geotextile tubes, tied sheet pile walls, and trestles were utilized to overcome the very large tidal difference between ebb and flow at the foreshore site. 44 circular-cell type dolphins surround the piers near the navigation channel to protect the bridge against the collision with aberrant vessels. Each dolphin structure consists of the flat sheet piled wall and infilled aggregates to absorb the collision impact. Geo-centrifugal tests were performed to evaluate the behavior of the dolphin in the seabed and to verify the numerical model for the design. Rip-rap embankments on the seabed are expected to prevent the scouring of the foundation. Prefabricated vertical drains, sand compaction piles, deep cement mixings, horizontal natural-fiber drains, and other subsidiary methods were used to improve the soft ground for the site of abutments, toll plazas, and access roads. Light-weight backfill using EPS blocks helps to reduce the earth pressure behind the abutment on the soft ground. Some kinds of reinforced earth like as MSE using geosynthetics were utilized for the ring wall of the abutment. Soil steel bridges made of corrugated steel plates and engineered backfills were constructed for the open-cut tunnel and the culvert. Diverse experiences of advanced designs and constructions from the Incheon Bridge project have been propagated by relevant engineers and it is strongly expected that significant achievements in geotechnical engineering through this project will contribute to the national development of the longspan bridge technologies remarkably.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.13-22
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• 2008

Fourteen calibration ehamber tests were performed using one cylindrical and two tapered piles with different taper angles to investigate the changes of the bearing capacity of tapered piles with soil state and taper angle of piles. The results of calibration chamber tests show that the ultimate base resistance of tapered piles increases with increasing mean stress and relative density of soil. It also increases with increasing taper angle for medium sand, but with decreasing taper angle for dense sand. The ultimate shaft resistance of tapered piles increases as vertical and horizontal stresses, relative density and taper angle increase. Based on the results of model pile load tests, a new design method with shape factors for estimation of the bearing capacity of tapered piles is proposed considering the effect of soil state and taper angle on bearing capacity of tapered piles. In order to check the accuracy of predictions calculated using the new method, middle-scale field pile load tests were also conducted on cylindrical and tapered drilled shafts in clayey sand. Comparison of calculated values with measured ones shows that the new design method produces satisfactory predictions tor tapered piles.

• The Journal of Engineering Research
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• v.6 no.1
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• pp.83-96
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• 2004

A soil mailed wall is adapted as road widening measure and is constructed under a miniature abutment built on steel pipe piles. The soil nailed wall called for removal of the existing embankment slope to permanently retain the fill behind the abutment. The soil nailed wall is fully instrumented and is monitored. A 3D finite element analysis is used to study further the behavior of the soil nailed wall. The complete sequence of construction is simulated. The numerical model is calibrated against the instrumented nailed wall. Then a parametric study is conducted. The results provide valuable information related to the effect of the excavation and nailing on the following: axial load and bending moment in the piles, load in the nails, and wall deflections.