• Title/Summary/Keyword: ground strain

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Short-term Variation in Class A Pan Evaporation (대형증발계 증발량의 일 변화)

  • 이부용
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.4 no.4
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    • pp.197-202
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    • 2002
  • A new method is used to estimate the amount of water evaporation from Class A Pan with higher precision and accuracy. The principle of method is to detect the weight change of a buoyant sinker resulting from a change in water level of Class A Pan. A strain-gauge load cell is used to measure the weight change. Field observation of evaporation was done at Pohang Meteorological Station from June 24 to August 4, 2002. By using this new method, it is possible to measure hourly evaporation accurately even under a strong solar radiation and wind disturbance, enabling a direct comparison of evaporation with other meteorological elements. At night, under low humidity and high wind speed conditions, more evaporation was recorded than during daytime. Maximum evaporation rates observed during this period exceed 1.0 mm/hour under the sunny and windy conditions with low humidity. To understand relationships between meteorological elements and latent heat flux at ground level, we suggest intensive held experiments using high accuracy evaporation recording instruments with hourly time interval.

Compressive Strength Tests on Frozen Siberian Clay (시베리아 동토지역 점성토의 압축강도 시험)

  • Kim, Young-Chin;Martin, Christ
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.97-104
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    • 2008
  • The objective of this study was to investigate the strength characteristics of frozen clay. Compressive strength tests were performed on frozen clay with different water contents at various temperatures. The dry density of specimens and strain rate was kept constant. Test results showed that compressive strength increased with increasing water content and decreasing temperature. The increase in peak strength became more significant the lower the temperature for a given water content. The failure mode changed from brittle to ductile deformation with increasing water content and decreasing temperature. Tests also showed an increase in deformation modulus with increasing peak strength, increasing water content and decreasing temperature.

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A study of dynamic peoperties in cyclic simple shear test (동적단순전단 시험기를 이용한 매립지반 거동특성에 관한 연구)

  • Kim, Sung-Jin;Ryu, Jeong-Ho;Park, Yo-Hwan;Kim, Jin-Man
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1422-1430
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    • 2008
  • Cyclic simple shear test apparatus was used to investigate the dynamic response of liquefiable soils as reclamation material. The specimen were reclamation using simple air-pluviation method. The confining stress was applied the range of 100 kpa to 200 kpa. The resulted strain was in the range of $10^{-3}$ ~ 5 %. Based on these test results modulus reduction curve, damping curve and cyclic strength curve were developed. The developed curves were compared to those already available in literature. The obtained curves can be applied to FEM or equivalent linear analysis such as SHAKE for ground response analysis.

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An Experimental Study on the Use of the Recycled Thick Aggregate Using Ceramic Bricks (소성벽돌의 콘크리트 재생골재 사용 가능성에 관한 실험 연구)

  • Kwon, Ki-Hyuk;Kim, Hyoung-Jun;Yu, Hye-Ran
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.501-504
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    • 2006
  • Recently, the Ceramic Bricks are getting increased due to demolishing aged buildings. But, disposal of the waste ceramic bricks has been relied on just burying into the ground. Regardless they can be used with recycled thick aggregate. Therefore the range of this study includes the experiment of slump test, compression, strength test and stress-strain analysis to the concrete the recycled thick aggregate with made by ceramic bricks. The reducing method of fine aggregate will be reviewed stand on analysis of this experimental result.

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Study of Soil Nailing Application as a Reinforcement Method for Slided Slope (붕괴사면보강을 위한 Soil Nailing의 적용성에 관한 연구)

  • 이성철;김명학
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.127-134
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    • 2000
  • Soil nailing is in-situ ground improvement technique of reinforcing soils using passive inclusions for the purpose of slope stability. Also soil nailing, in general, was used and studied as a reinforcement technique at cut slope, but this paper presents the results of study for soil nailing application as a reinforcement technique at the banking over slided slope. In-situ pull-out tests of nails, instrumented with strain gauges, were performed to investigate the maximum pull-out load and to calculate the unit side resistance in each different layer. And the apparent average unit side resistance of this study was compared with that of other sites installed at cut slope.

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Model Test for the Damage Assessment of Adjacent Frame Structures in Urban Excavation (지반 굴착에 따른 인접 프레임구조물의 손상평가에 관한 모형실험 연구)

  • Kim, Seong-Cheol;Hwang, Eui-Seok;Kim, Zu-Cheol;Kim, Hak-Moon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1490-1495
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    • 2005
  • In this study, Model test of concrete frame structures with various shapes and locations are carried out by means of applying Peck's(1969) settlement method. The results of the model test indicated that important correlations existed between the behavior of frame structure and ground movement. Also, the damage level of frame structure closely influenced by the phase of excavation. Therefore, prediction of damage level at early phase of construction should be very precise. The damage level graph by Cording et al.(2001), the angular distortion provided gradually more serious damage to frame structures for the all cases. But the damage level graph by Burland(1997), was difficult to confirm because of very small amount of deflection ratio.

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Application on Geotextiles for the Roadbed Reinforcement of the Concrete Track Rehabilitation (콘크리트궤도 개량공사시 노반 보강을 위한 토목섬유의 적용)

  • Lee, Il-Wha;Jang, Seung-Yup;Han, Sung-Wu;Kim, Yong-Jin
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1802-1806
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    • 2007
  • The most important factor is the roadbed bearing capacity at concrete track construction. Particularly, in case of rehabilitation, it is essential to secure the uniform roadbed stiffness to prevent the irregular settlement. In this study, reinforced effect of the geotextiles is investigated which is applied to concrete track rehabilitation. The geotextiles is installed two or three layers as the condition of the ground and structure. The reinforced effect of geotextiles is confirmed by the strain gage attached on the geotextiles surface.

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Numerical Analysis on the Behavior of a Colluvium Slope Reinforced with Soil Nails and Anchors (소일네일과 앵커로 보강된 붕적층 비탈면의 거동에 관한 수치해석)

  • Jang, Myoung-Hwan;Kim, Hoon-Tae;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.33 no.A
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    • pp.73-80
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    • 2013
  • This paper is results of numerical analysis on the behavior of colluvium slope with combinations of soil nails and earth anchors during excavation. In order to maintain the stability of the colluvium cut, being composed of gravel and boulder and thus local in stability being expected during slope cut, temporary reinforcing method of soil nailing with shotcrete might be used. Subsequent method of cast-in-place facing with earth anchors can be used to maintain cut slope stable permanently. For the cut slope where these methods had been applied, the numerical techniques were applied to their behaviors and investigate the stability of the slope. Limit equilibrium methods were used to confirm to maintain the slope stability during and after excavation and application of those reinforcing methods. Another numerical technique of FEM was also used to find the stress and strain as well as deformation distribution in reinforcing materials and slope ground during excavation.

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Model Test and Numerical Analysis for Failure Behaviour of Shallow Tunnel Considering Unsupported Tunnel Length (굴진장을 고려한 얕은 터널파괴거동에 대한 모형실험 및 수치해석)

  • Kim, Young-Min
    • Tunnel and Underground Space
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    • v.15 no.6 s.59
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    • pp.400-410
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    • 2005
  • During excavation of shallow tunnels in soft ground, failure mechanism around the tunnel face have major influence on the stability of tunnels. In this paper, a series of laboratory tests under plane strain condition on the small scale of a shallow tunnel considering unsupported tunnel length has been performed. The results have shown that tunnel failure mechanism changes from failure mode 1 to failure mode 2 as unsupported tunnel length increases. By comparing the experimental and the numerical results, the loosening pressure for the shallow tunnel and progressive failure have been investigated.

Development of Functional Sports-brassiere (기능적 Sports-brassiere 개발에 관한 연구)

  • 최혜선;손부현
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.3
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    • pp.452-466
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    • 1996
  • The purpose of this study is to proviede basic data for designing sports-brassiere by a questionnaire survey about sports-brassieres preferences and physiological wearing test. The results of the survey and the physiological wearing tests on sports-brassieres are as follow; 1. According to the survey, dissatisfied factors on the sports-brassiere are "drooping and vibrating of the breasts". Preferable factors are supporting breasts by stretch and seldom changing its position by motion. The bigger cup-size and more hemispherical-type causes more discontent than flat-type. 2. The shape of breasts is oval, on what ground, horizontal line is longer than vertical. For the cross section of bust line, shirts type.brassiere is more gently curved than cup-brassiere. 3. The feeling of wearing comfort is correlated with bust.up, shield, close adhesion. The vibration of breasts is correlated with covering urea and close adhesion, and the changing band's position by movement, close adhesion. Too much covering area or strain are in inverse correlation of the comfort. 4. The rate of prevention of vibration is 75~80% on superior sports-brassieres, which has broad covering area and excellent close adhesion. adhesion.

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