• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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• pp.1-10
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• 1999

In the present study, laboratory pull-out tests with various geogrid shapes are carried out to investigate behavior characteristics of the geogrid. Also, an interface pullout formula is proposed for predicting and interpreting pullout test result. The analytical model is based on the assumption that the reinforcement is linear elastic during the pullout test. And then, maximum pullout force, frictional resistance and active length for each of the grid density ratio are predicted based on the interface pullout formula. The predicted results were compared with those of pullout tests, and showed in general good agreements.

• 한국해양공학회지
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• 제16권2호
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• pp.44-52
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• 2002

The mechanism of pullout resistance of compression anchor is analysed. This anchor is developed through the field pullout tests and the laboratory element test. The compression anchor is characterized by decrease of progressive failure, simple site work, economy and durability compared with tension anchor. The characteristics of compression anchor, compared with tension anchor. mainly are summarized as follows ; (1) The plastic displacement of anchor body is very small during pullout of anchor. (2) Total anchor length decreases by the shortening of free length; (3) The progressive failure is decreased.; (4) The safety factor for pullout resistance increases with time after construction of anchor.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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• pp.11-20
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• 1999

The method which makes the soft ground reinforced by using the geogrid, a kind of geosynthetics has been getting popular and its usefulness also has been increased due to reduction in costs, ease of construction and great exterior view, But the study on the frictional characteristics, which is the important factor in design, between reinforcement and soil is insufficient. In this study, compaction degrees were considered through large-scale pullout tests. As a part of studying on estimation of pullout frictional characteristics between soil and geosynthetics, pullout tests were peformed and from the result of pullout tests, pullout frictional parameters between soil and geosynthetics were obtained and pullout behaviors were learned.

• 한국지반신소재학회논문집
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• 제12권4호
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• pp.57-66
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• 2013

본 연구에서는 산업폐기물인 저회와 폐어망을 각각 뒤채움 재료와 보강재로 재활용하기 위하여 저회와 폐어망 사이의 인발특성을 분석하였다. 이를 위해 저회로 구성된 지반에 망목크기가 다른 3종류의 폐어망(WFN20 : $20mm{\times}20mm$, WFN30 : $30mm{\times}30mm$, WFN40 : $40mm{\times}40mm$)과 지오그리드를 보강재로 사용하여 인발시험을 수행하였다. 인발시험 수행 결과, 지오그리드와 동일한 망목크기를 갖는 WFN20의 인발마찰각은 지오그리드와 유사하게 나타났다. 이것은 WFN20의 인장강도와 강성은 지오그리드 보다 작으나, WFN20의 두께가 지오그리드 보다 커서 횡리브에 의한 지지력이 발현되었기 때문이다. 보강재의 잔류변형률 분포는 연직응력에 의존한다. 연직응력이 증가함에 따라 보강재 선단에 인발력이 크게 집중되어 변형이 크게 나타난다.

• 한국지반공학회논문집
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• 제30권1호
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• pp.5-16
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• 2014

본 논문에서는 현장인발재하시험을 통한 스크류 앵커 파일의 인발 저항 특성에 관한 연구내용을 제시하였다. 현장시험에서는 동일한 피치를 가지나 샤프트나 스크류 직경이 다른 스크류 앵커 파일에 대해 다양한 시공조건을 도출하고 이에 대한 시험을 수행하였다. 실험결과 스크류 앵커 파일은 스크류가 없는 파일에 비해 현저히 큰 인발저항력을 발휘하는 것으로 검토되었으며 시간경과 효과와 그라우팅 여부에 따른 검토 결과 일반 파일과 유사하게 시간경과에 따라 인발저항력이 증가하는 셋업효과와 그라우팅시 인발저항력 상승효과를 기대할 수 있는 것으로 분석되었다. 이와 아울러 기존의 헬리컬 파일의 인발저항력 산정식을 스크류 앵커 파일의 인발저항력 평가에 있어서의 적용성을 검토하였으며 현장인발재하 시험결과를 다양한 측면에서의 상관관계를 파악할 수 있도록 제시하고 연구결과의 실무적 관점에서의 검토 내용을 기술하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.819-824
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• 2005

Anchor system is widely used in construction works to support retaining structures. The compression anchor is characterized by excellent mechanism of pullout resistance, as well as less probability of progressive failure than a tension anchor. This paper presents the mechanical characteristics of a newly developed compression anchor(JR-2000). Field tests were performed to investigate characteristics of the pullout resistance of compression anchor.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.419-426
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• 2002

In this study, the steel strip reinforcement bolted with braced angles is displayed skin friction resistance as well as passive resistance through existing the steel strip reinforcement. To understand pullout behavior characteristics, friction effects between soil and reinforcement are evaluated with the width of reinforcement, magnitude of surcharge, and existence of passive resistance member through laboratory pullout test. To analyze interference effects for passive resistance member, various tests are carried on case that the number, the location, and the spacing of braced angles are different. Using this test result, pullout resistance factor is calculated to consider location of braced angles and degree of interference for spacing ratio.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1079-1083
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• 2009

In this study, the pullout resistance characteristic of a wedge-shaped soil nail, made by attaching small steel sticks to the tip of a nail in a wedge shape, was investigated. It was developed to improve the overall pullout resistance capacity of the existing soil nail system, composed of nail and grout, by making the wedge provide additional pullout resistance. In order to evaluate the pullout resistance of the wedge shape-soil nail, field pullout tests were conducted, and the results were compared with those for the existing soil nail without the wedge. The field test results showed that the pullout resistance capacity of the wedge-shaped soil nail was 50% larger than that of the existing soil nail without the wedge.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.87-97
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• 2014

In this study, the model tests were conducted on the short piles installed in sands under a horizontal pullout load to investigate their behavior characteristics. From the horizontal loading tests where dimensions of the pile diameter and length, and loading point were varied, the horizontal pullout resistance and the rotational and translational movement pattern of the pile were investigated. As a result, the horizontal pullout resistance of the pile embedded in sands was dependent on the pile length, diameter, loading point, etc. The ultimate horizontal pullout load tended to increase as the loading point (h/L) moved to the bottom from the top of the pile, regardless of the ratio between the pile length and diameter (L/D), reached the maximum value at the point of h/L = 0.75, and decreased afterwards. When the horizontal pullout load acted on the upper part above the middle of the pile, the pile rotated clockwise and moved to the pullout direction, and the pivot point of the pile was located at 150-360mm depth below the ground surface. On the other hand, when the horizontal pullout load acted on the lower part of the pile, the pile rotated counterclockwise and travelled horizontally, and the rotational angle was very small.

• 대한의용생체공학회:의공학회지
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• 제42권1호
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• pp.1-6
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• 2021

Recently, various types of pedicle screws have been developed considering the anatomical structure of the spine. The purpose of this study was to evaluate the pullout stiffness and strength of two types of commercial pedicle screws. The design of two type screws were single pitched thread (ST) pedicle screw and dual pitched thread (DT) pedicle screw, respectively. The tests were conducted in accordance with the ASTM standards using polyurethane (PU) test blocks which has anatomical structure of the spine. There was no significant difference in pullout stiffness between two types of screw. However, DT exhibited higher pullout strength than ST (p<0.05). Pedicle screw with dual pitched thread showed higher pullout strength without decrease in pullout stiffness compared to the standard pedicle screw. In conclusion, dual pitched thread design of the pedicle screw is considered to be more suitable than the single pitched thread for the anatomical structure of the spine.