• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.589-596
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• 2002

In this study, static pile load tests with load transfer measurement were accomplished in the field. Yield pile capacity (or ultimate pile capacity) determined by load-settlement-time relationship was determined and axial load transfer behavior was analyzed. In the test for the four test piles were behaved as end bearing pile but ratios of skin friction to total pile capacity were 27%∼33%.

• Geomechanics and Engineering
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• 제18권3호
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• pp.315-328
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• 2019

This paper presents an investigation on bearing capacity, load-settlement behavior and safety factor of rock-soil slopes reinforced using geogrid-box method (GBM). To this end, small-scale laboratory studies were carried out to study the load-settlement response of a circular footing resting on unreinforced and reinforced rock-soil slopes. Several parameters including unit weight of rock-soil materials (loose- and dense-packing modes), slope height, location of footing relative to the slope crest, and geogrid tensile strength were studied. A series of finite element analysis were conducted using ABAQUS software to predict the bearing capacity behavior of slopes. Limit equilibrium and finite element analysis were also performed using commercially available software SLIDE and ABAQUS, respectively to calculate the safety factor. It was found that stabilization of rock-soil slopes using GBM significantly improves the bearing capacity and settlement behavior of slopes. It was established that, the displacement contours in the dense-packing mode distribute in a broader and deeper area as compared with the loose-packing mode, which results in higher ultimate bearing load. Moreover, it was found that in the loose-packing mode an increase in the vertical pressure load is accompanied with an increase in the soil settlement, while in the dense-packing mode the load-settlement curves show a pronounced peak. Comparison of bearing capacity ratios for the dense- and loose-packing modes demonstrated that the maximum benefit of GBM is achieved for rock-soil slopes in loose-packing mode. It was also found that by increasing the slope height, both the initial stiffness and the bearing load decreases. The results indicated a significant increase in the ultimate bearing load as the distance of the footing to the slope crest increases. For all the cases, a good agreement between the laboratory and numerical results was observed.

• Computers and Concrete
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• 제21권4호
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• pp.385-397
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• 2018

This study is focused on the investigation for similitude the requirements between prototype and scaled models to determine the structural behavior of concrete load bearing systems. The scaling concept has been utilized in many engineering branches, has been assisted to engineers and scientists for obtain the behavior of the prototype by using scaled model. The scaling can be done for two purposes, either scaling up or scaling down depending upon the application. Because, scaled down models are the experimentation on scaled models is cheaper than huge structures. These models also provide facilities for experimental work. Similarity relationships between systems are created either by field equations of the system or by dimensional analysis. Within this study, similarity relationships were obtained by both methods. The similarity relations obtained are applied to different load bearing systems and it is determined that the similarity relation is a general expression. In this study, as an example, column, frame, cantilever beam and simple beam are chosen and 1/2, 1/5 and 1/10 scales are applied. The results are compared with the analytical results which are obtained by creating of the finite element models with SAP2000 software of different scaled load bearing systems. The analysis results of all systems are examined and it is determined that the scale factors are constant depending on the scale types for different load bearing systems.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 가을 학술발표회 논문집
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• pp.391-398
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• 1997

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6322-6328
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• 2014

얕은기초의 하중지지거동을 살펴보기 위해 3종류의 얕은기초를 가정하여 유한요소해석을 수행하였다. 띠기초에 대한 해석을 통해 구한 파괴시의 기초하부지반의 파괴양상은 팽창각이 없는 경우 국부전단파괴양상을 보였으며 팽창각이 있는 경우에는 전반전단파괴양상을 보였다. 팽창각에 따른 극한하중에 있어서는 팽창각이 있는 경우의 극한하중이 팽창각이 없는 경우에 비해 1.5배 큰 값을 보였다. 원형기초와 정사각형 기초에 대한 해석결과에 따르면 팽창각의 존재여부와 관계없이 파괴시 기초 인접지반면에 상향의 변위가 발생하여 전반전단파괴양상을 보였다. 극한하중에 있어서는 팽창각이 있는 경우가 없는 경우에 비해 약 10% 정도 증가하였다. 세 종류의 얕은기초에 대하여 해석을 통해 얻은 하중-침하곡선을 살펴볼 때 팽창각이 클수록 하중지지능력이 큼을 알 수 있었다.

• 산업기술연구
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• 제21권B호
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• pp.205-212
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• 2001

This paper is experimental and numerical research about the sliding behavior of cantilever retaining walls resisting surcharge loads. In experimental research, centrifuge model tests at the lg and 40 g-level were performed by changing the location of model footing and its width. Bearing capacity of model footing and characteristics of load-settlement and load-lateral displacement of retaining wall were investigated. Test results of bearing capacity were compared with modified jarquio method, based on the limit equilibrium method with elasticity theory. For the numerical analysis, the commericially available program of FLAC was used by implementing the hyperbolic constitutive relationships to compare with test result about load-settlement and load-displacement of retaining wall, bearing capacity of strip footing.

• 한국철도학회논문집
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• 제3권2호
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• pp.84-91
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• 2000

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. With the test results, the bearing capacity ratio, elastic rebound ratio, subgrade modulus and the strain of geogrids under loading were investigated. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to estimate the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• 한국지반공학회논문집
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• 제16권1호
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• pp.107-116
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• 2000

4개 현장에 실물크기의 강관말뚝과 PC 및 PHC 말뚝의 축방향에 대한 지지거동을 알아보기 위하여, 강관말뚝에 스트레인게이지를 부착하고 항타시 계측기 손상여부를 조사하면서 동재하시험을 수행하였다. 아울러 동일한 말뚝에 대하여 2일과 7일 경과후에 정재하시험을 실시하여 하중-침하량 거동과 주면 및 선단지지력을 분리 측정하였다. 그 결과, CAPWAP 해석에 Davisson방법을 적용하여 구한 강관말뚝의 허용지지력은 정재하시험에서 구한 허용지지력 보다 약 2~33%정도 크게 나타났다. 그리고 정재하시험 결과에서 구한 산술평균한 허용지지력은 CAPWAP해석에서 Davisson's offset방법으로 구한 허용지지력보다 극한지지력에 FS=2.5를 적용하여 구한 허용지지력에 더 근접하는 경향을 보였다. 또한, 단위면적당 주면지지력은 깊이가 증가함에 따라 증가하였고, 말뚝선단부 1~2m 이내에서 발휘되는 비율이 상당히 큰 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.599-605
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• 2009

The aim of the present study is the characteristics of bridge rubber pads and suggested how to determine the stiffness the pads. A disk bearing is operated as an elastic bearing in the vertical direction and is composed of a Polyether Urethane (polyurethane) disk for elastic support and Polytetrafluoroethylene (PTFE) to accommodate movement. Static tests are conducted in a laboratory to determine the static behavior of a Polyurethane disk. Finite Element (FE) analysis is also performed to verify the static performance. For dynamic behavior, four disk bearings having the identical Polyurethane disk used in the static tests are installed in a full size railway bridge and tested under a running locomotive. From the tests results, the static and dynamic stiffness of disk bearings are estimated and compared with each other. In the procedure to estimate the stiffness of a pad, the dead load(pre-load) of a bridge and live load of a vehicle are considered.

• Geomechanics and Engineering
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• 제6권1호
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• pp.33-45
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• 2014

Use of geotextile as reinforcement material to improve the weak soil is a popular method these days. Tensile strength of geotextile and the soil-geotextile interaction are the major factors which influence the improvement of the soil. Change in fine content within the sand can change the interface behavior between soil and geotextile. In the present paper, the bearing capacity of unreinforced and geotextile-reinforced sand with different percentages of fines has been studied. A series of model tests have been carried out and the load settlement curves are obtained. The ultimate load carrying capacity of unreinforced and reinforced sand with different percentages of fines is compared. The interface behavior of sand and geotextile with various percentages of fines is also studied. It is observed that sand having around 5% of fine is suitable or permissible for bearing capacity improvement due to the application of geosynthetic reinforcement. The effectiveness of the reinforcement in load carrying capacity improvement decreases due to the addition of excessive amount of fines.