• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.744-751
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• 2006

In case of the Soil Nail System applied to a slope, effects of vibrations from blasting, earthquake and creep of long term behaviors cause reductions of adhesion between grout and soil-nail. There are some reports of nail's pull-out failure by those reasons. In this paper it is suggested that the Cone Nailing System is enable to diminish effects of vibrations and creep. In this study on Cone Nailing System, the cones are installed to each nail by 2m. By such installing cones, the adhesion between nail and grout will increase and the long term creep behavior will decrease. In this study, the centrifuge test is performed to understand the behaviors of the Cone Nail System. For the centrifuge test, the soil tank is 52cm in width, 17cm in length and 35cm in height. In comparison with general soil nail, the centrifuge test of general soil nail(without cone) is performed equally. Additionally, the interface between cone nail and soil through the pull-out test is applied to FLAC 2D version 3.3. and the evaluation of application for the Cone Nail System in slope is performed.

• 지질공학
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• 제30권1호
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• pp.59-69
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• 2020

CPR 시험말뚝에 대해 인발재하시험을 실시하고, 하중-변위 곡선과 하중-침하량 곡선을 분석한 후 항복하중과 허용지지력을 산정하여 주면마찰력을 평가하였다. 하중-변위 곡선으로부터 분석된 CPR 시험말뚝의 결과에 의하면, CPR 시험말뚝의 직경이 큰 경우의 항복하중과 허용지지력이 작은 경우보다 약 1.4배 이상 크게 나타났다. 하중-침하량 곡선으로 부터 분석된 결과에 의하면, CPR 시험말뚝의 직경 D500의 허용지지력이 D400보다 약 1.2~2.1배 큰 것으로 나타났다. 하지만, Fuller 분석에 의해 산정된 허용지지력은 P-S 곡선과 log P - log S 곡선에 의해 산정된 허용지지력과 큰 차이를 보여, Fuller 분석에 의한 허용지지력 산정은 적절하지 않은 것으로 판단되었다.

• 대한치과교정학회지
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• 제42권1호
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• pp.39-46
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• 2012

Objective: We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. Methods: We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), $0.016{\times}0.022$-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out force, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. Results: Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). Conclusions: Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers.

• 콘크리트학회논문집
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• 제22권6호
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• pp.833-841
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• 2010

이 연구에서는 5개의 철근콘크리트 보-기둥 접합부 실험을 분석하였다. 연구의 주목적은 접합부에 인접한 보의 소성힌지의 영향으로 인한 부착 감소로 발생하는 보 주인장철근 미끄러짐에 따른 접합부 내력 및 연성을 평가하는 것이다. 또한 보 주인장철근량을 변수로 하여 접합부 내력 및 연성에 미치는 영향을 평가하였다. 실험 결과에 의하면 접합부의 전단강도비 $V_{j1}/V_{jby}$가 감소할수록 인접한 보의 소성힌지의 변형률 침투현상은 증가하는 것으로 나타났다. 주인장철근의 미끄러짐은 구간별로 다르게 나타났으며 주인장철근 뽑힘 현상은 접합부 전단강도비 $V_{j1}/V_{jby}$와 관계없이 비슷하게 나타났다. 이것은 주인장철근 뽑힘 현상이 변형률 침투현상만이 아닌 인접한 보의 소성힌지의 축변형에도 영향을 받기 때문이다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.353-358
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• 2001

The cement concrete pavements are designed twenty years of performance life in Korea. At the present time, some expressways have been elapsed seventy percent of performance life which are detecting local failures. The most repair methods using to repair failures are partial depth repair and full section repair. These methods are most important bonding strength between rapid curing materials and substrate concrete pavements. This study was performed to evaluate bonding strength of the composites section made of rapid curing material and substrate concrete pavements. The pull-out tester was used to test bonding strength for the composites section made of each materials. In the results of the test, the bonding strength values of the epoxy mortar and acrylic mortar are higher than those of the other materials. The performance life of repaired section is affected by various factor. The bonding strength of bonded composites section may be affect the performance life, significantly.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.496-503
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• 2000

The friction between soils and the geosynthetics varies depending upon the types and characteristics of the involved materials. Many engineers have studied the frictional characteristics between the two materials in may way but the results obtained so far is not satisfactory. In this study the frictional characteristics between the soil and the geogrid were examined through laboratory direct shear test and pull-out test. Tests were conducted on two different types of geogrid: Polyester grids(PET) which are currently used and newly developed fiber-glass grids(FG). Result showed that FG grid yielded smaller displacements and uniform displacement distribution mainly due to much higher stiffness. Therefore, it is expected that more efficientbfl support and displacement control can be achieved by the FG grid.

• 수산해양기술연구
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• 제40권2호
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• pp.161-165
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• 2004

The main goal of this work is to study the effect of glass fiber volume fraction on the result of tensile test with respect to glass fiber/polypropylene(GF/PP) composites. The tensile test and failure mechanisms of GF/PP composites were investigated in the fiber volume fraction range from 10% to 30%. The tensile strength and the fracture strength increased with the increasing of the fiber volume fraction in the tested range. Fiber pull-out and debonding of this composites increased with the fiber volume fraction in thc tested range. The major failure mechanisms were classified into the debonding, the fiber pull out, the delamination and the matrix deformation.

• 조명전기설비학회논문지
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• 제24권9호
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• pp.49-55
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• 2010

Many electric poles in the softground have been collapsed due to external load. In this study, 10 types of tests were performed with variation of location, numbers and depths of anchor blocks as well as depth of poles to find stresses acting on concrete electric poles. The stresses of concrete poles are relaxed at 600~700[kg] of tensile load, and stresses are concentrated at top of pole, and spread to lower part of pole. In the concrete pole collapse test, tensile load at failure was approximately 1,400[kg], which is twice of design load. As passive zone in the soil increases, the stresses acting on concrete pole are concentrated at lower part of pole based on moment arm earth pressure distribution.

• 한국지반환경공학회 논문집
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• 제24권4호
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• pp.13-22
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• 2023

본 논문에서는 시험적 연구를 통해 록볼트가 지보효과를 발휘하는 시기를 그라우트 강도로 제시하고, 수치해석적 연구를 통해 지반조건과 경계면 강도감소계수에 따른 록볼트 인발 거동을 분석한 연구를 다루었다. 그 결과 록볼트는 그라우트 강도 5 MPa(재령 18시간)에서 지보효과를 발휘하였으며, 경계면 강도감소계수의 영향은 록볼트 변위의 경우 연약한 지반일수록, 그라우트- 지반의 전단응력의 경우 지반의 탄성계수가 높을수록, 그라우트 응력의 경우 모든 지반조건에서 영향이 큰 것으로 분석되었다. 이러한 연구결과는 록볼트 인발시험의 구체적인 기준 재정립과 록볼트 수치해석에 도움이 될 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.640-648
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• 2009

Recently the truction of coastal reclaimation work has been extensively implemented in Korea. The Sondo New City is being established on the reclaimed land from the sea, construction companies of metro construction are planing to pull-out the sheet pile for saving the construction cost. In the case of soft marine clay, it is very difficult to pull-out the sheet pile by using the hydraulic hammer difficult. Therefore, the man of the field must be aware of vibration effect to the ground and the structure. For understanding the vibration effect to the ground during subway construction, the model was formulated with 1/25 braced-cut for subway construction. Scott and Iai(1989) proposed the law of the similarity for other experimental conditions. The laboratory model test was conducted under the vibration condition of sheet pile pulling out. The settlement on the ground surface was measured during the shaking table test. The pore water pressure was also monitored in the upper, middle, and lower layers of soil. The field settlement level and the pore water pressure can be predicted by using the results of the laboratory shaking table test.