• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.573-584
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• 2013

This study experimentally investigated the change in distribution of wave pressure on the front wall according to the variation of the front wall porosity of the caisson breakwater having the cap of wave chamber. First, the wave pressure for the non-porous caissson corresponding to zero porosity was measured and compared with the pressure formula suggested by Goda(1974). The analysis showed that the measured pressure distribution fairly well agreed with the Goda formula, which confirmed the accurate measurement of wave pressure in the present experiment. In case of the porous caisson, meanwhile, the experiment was performed by varying the front wall porosity as 0.2, 0.25, and 0.3. The wave pressure distribution at the front wall showed little difference according to the porosity for most of the test wave conditions, whereas the pressure slightly increased with the porosity for some test waves whose wave heights and periods were relatively large. However, the difference according to the porsosity was insignificant for the wave force at the front wall.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.1-7
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• 2010

The soil nailing method have been developed on the basis of experimental works as well as theoretical backgrounds. As for the experimental research works, most of the data have been measured during the application of load in service. However, not only the soil-nailed structure behavior in service but also the failure behavior of the structure are the major concerns to evaluate and even establish a design method of soil-nailed walls. In this paper for the apprehension of behavior in the soil-nailed structure which the front of nail is connected, a relatively large-scale experiment was carried out to figure out the failure behavior of soil-nailed wall. A number of data have been acquired and analysis.

• Journal of the Korean Geosynthetics Society
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• v.11 no.3
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• pp.43-51
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• 2012

This paper describes the stability evaluation of reinforced earth wall using geosynthetic strip based on field test. The wall facing, which is applied in field, is able to present excellent scenery, and the reinforcement has improvement effect of pullout resistance based on rounded band anchor. The measurement is conducted according to construction elapsed time of structure for earth pressure, horizontal displacement of wall facing and reinforcement strain in field test. The evaluation results show that the measured earth pressure is less than theoretical earth pressure due to dispersion effect of earth pressure by geosynthetic strip. The horizontal displacement of wall facing is also satisfied a empirical criteria. The measured strain of reinforcement had nearly no effect on stability of the reinforced earth wall. Therefore, the geosynthetic strip with rounded band anchor can be applied in the reinforced earth wall, and the reinforced earth wall with geosynthetic strip can be commonly used in field because it has a structural stability.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.241-244
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• 1997

This paper proposes Electronic Speckle Pattern Interferometry(ESPI) for the quantitative buckling analysis of square tube, which is unable to be measured with previous methods. The quantitative buckling analysis in elasticity is important part to study strain-stress analysis of thick-plated tube and fatigue analysis. However, it is unsolved problem with theory and previous experimental method. The merits of ESPI, Whole-filed measurement and high accurate 3D-displacement measurement make it possible to determinate the buckling analysis in elasticity quantitatively.

• Journal of the Korean Geosynthetics Society
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• v.4 no.2
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• pp.47-56
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• 2005

Recently, geosynthetic reinforced earth walls are gradually replacing conventional concrete retaining walls for reasons of economy, expediency of construction, and aesthetics. A number of reinforced soil walls having more than 10m heights have been constructed to make more effective development in the country. However, mistakes in design and construction of reinforced earth walls have resulted in many troubles such as failure of reinforced earth walls, horizontal deformationor breakdown of facings, and so forth during or after construction. In this paper, a case study on global sliding failure of a geogrid-reinforced tiered wall is carried out to investigate the causes of the failure and suggest the proper countermeasures. From the subsurface investigation and field instrumentation, It is found that the cause of the global sliding failure was occurred by decreasing of bearing capacity of foundation ground induced by infiltration of rainwater.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.41-49
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• 2014

The 3D numerical analysis is carried out to investigate the settlement behavior of flexible mat foundations subjected to vertical loads. Special attention is given to the improved analytical method (YS-MAT) that reflects the mat flexibility and soil spring coupling effect. The soil model captures the stiffness of the soil springs as well as the shear interaction between the soil springs. The proposed method has been validated by comparing the results with other numerical methods and a field measurement on mat foundation. Through comparative studies, the settlement of the proposed method was in relatively good agreement with those of a field measurement and other numerical methods. The results permit us to estimate the response of the mat foundation subjected to vertical loads that should be taken into account in the combination of mat flexibility and soil continuity characteristics.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.97-105
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• 1997

급속히 변화하는 현대사회에서 생활수준의 향상과 식생활의 서구화 및 신체의 활동량 감소, 과잉 영양공급으로 체중이 증가하여 체형의 변화가 일어난다. 이에 본 연구에서는 체형을 변화시키는 여러 요인 중에서 피하지방으로 인한 변화를 알아보기 위해 초음파 피하지망 계측기를 사용하여 20대 남성을 대상으로 19 .approx. 24세를 집단1, 25 .approx. 28세를 집단2로하여 각 집단간의 피하지방 분포경향과 각 집단간의 피하지방 계측피를 요인분석하여 남성복 의복제작 및 현대남성의 올바른 체형해석을 위한 기초자료 제공이 본 연구의 목적이다. 피하지방이 침착하기 쉬운 부위는 허리앞1/2과 배앞 1/2로 나타 났고, 피하지방이 침착하기 어려운 부위는 하퇴전면으로 나타났다. 피하지방두께 계측에서 집단간 유의 차 검증결과 20대 후반으로 연령이 증가함에 따라 작은 폭으로 지방침착이 일어났다. 집단1의 요인분석 결과 요인1은 허리부위, 요인2는 체간부1/2과 체간부 측면부위로 나타났다. 집단2의 요인분석결과 요인 1은 윗가슴부위와 허리부위, 요인2는 전체적부위로 나타났다. 전체집단에서는 요인분석결과 요인1은 상 지, 하지부위, 요인2는 허리부위로 나타났다. 연령의 증가와 함께 피하지방 침착이 체간부 하부인 허리 와 배를 중심으로 이루어지는 것으로 나타났다.

• Journal of the Korean Geotechnical Society
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• v.35 no.12
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• pp.35-44
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• 2019

In this study, the axial stiffness of reinforcing piles (K_vr) for the vertical extension remodeling structures was estimated through 3D finite element analysis. In the computation of the minimum required axial stiffness of reinforcing piles, proposed maximum axial stiffness of old and deteriorated existing piles (K_ve) based on theoretical and experimental approaches will be applied. Through this, the required increase rate of axial stiffness of reinforcing piles in order to support the increased structural loading was proposed for end-bearing and friction piles by different slenderness ratio (L/D). The numerical model was validated by comparing the computed results with actual field measurements. Based on the computed results, it was concluded that the end-bearing reinforcing pile needs 44% - 67% increase in axial stiffness to deal with the deterioration of existing piles and support the additional structural load due to vertical extension remodeling.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.51-61
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• 2016

New building methods are needed to aid increased inner-city redevelopment and industrial construction. A particular area of improvement is the efficient use of cut slopes, with the minimization of associated problems. A retaining wall of precast panels can resist the horizontal earth pressure by increasing the shear strength of the ground and reinforcing it through contact with the panels. Precast panels allow quick construction and avoid the problem of concrete deterioration. Other problems to be solved include the digging of borrow pits, the disposal of material cut from the slope, and degradation of the landscape caused by the exposed concrete retaining wall.This study suggest the methods of improvement of an existing precast panel wall system by changing the appearance of the panels to that of natural rock and improving the process of adhering the panel to a vertical slope. The panels were tested in the laboratory and in the field. The laboratory test verified their specific strength and behavior, and the field test assessed the panels' ground adherence at a vertical cutting. Reinforcement of the cutting slope was also measured and compared with the results of 3D numerical analysis. The results of laboratory test, identified that the shear bar increase the punching resistance of panel. And as a results of test construction, identified the construct ability and field applicability of the panel wall system adhered to in-situ ground. In addition to that, extended measurement and numerical analysis, identified the long-term stability of panel wall system adhered to in-situ ground.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.1
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• pp.47-54
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• 1993

Recently, collapse of structures is frequently occurred, so precautionary measures against accidents are requested. In this study, periodic deformations of structure are surveyed using C.R.P technique and these were used to estimate absolute deformation associated with geodetic network. Also, as compared with inclinometer outcome, correlation of these results was obtained. As a results of this study, a difficult problem of control survey was resolved as control points arranged on intervisible parts of structure. And the transformation parameters for absolute deformation analysis were determined incorporating reference network with control network. This eventually led to possibility for analysis of ground behavior, moreover we were able to overcome a limitation of traditional method that could measure only a part of objects.