• 국제초고층학회논문집
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• 제8권3호
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• pp.177-183
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• 2019

This paper describes the structural design of a 212 m tall building currently under construction in the Tokiwabashi District Redevelopment Project facing Tokyo Station. In this project there was a requirement to rationally solve many issues arising from the conditions of the redevelopment project. In particular, the following two points were considered to be important from the point of view of structural design. 1) To provide an overhang frame with the perimeter columns on the lower stories inclined, in order to enable a typical floor area that greatly exceeded the limitations of the underground structure shape. 2) To provide high grade seismic performance for the office buildings to be constructed on prime city center land. LSCVCS (Lower Stories Concentrated Vibration Control System) was proposed as the method of rationally designing the overhang frame, which is an extremely disadvantageous element in the structural scheme of the tall building with a large slenderness ratio. LSCVCS is a system to provide effective damping by arranging vibration control devices in a concentrated manner in a lower story with large story height, that produces large deformation in an earthquake. Also, the vibration control devices arranged in the lower story are limited to viscous devices, to take into consideration the residual deformation of the overhang frame after an earthquake. The results of investigations into the specific effects of the system for the seismic design are reported, including Performance-based seismic design.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1994년도 가을 학술발표회 논문집
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• pp.139-148
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• 1994

Rapid industrialization and urbanization caused by the high economic growth of the country requires optimization of land usage as well as the expansion of underground space. Therefore the construction of large and deep basements is inevitable in built up areas where the braced excavation for earth retaining structures may create many problems such as settlement and damages of nearby buildings and underground utilities. In this work, some of major influential factors concerning the stability of braced excavation are investigated and the results are compared with the field observation results. The ground water table, applied strut forces, horezontal wall displacement, infilling materials in the rock joints were found to be the most critical factors influencing the stability of braced walls constructed in the layered ground. Magnituide and type of the wall deformation was closely related to the pattern of the surface settlement. The stability of braced walls are described in terms of strut forces.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.425-428
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• 2005

To resolve land demand by the development of various industries and the cityward tendency of population, the construction of ultra-soft ground that is unused in the past has been progressing with activity. The ultra-soft ground has very small shear strength and large deformation, so leads to many problems in ground improvement in construction. In order to dispose of these problems, it is necessary to develope the chemical materials that can be applied to the surface stabilization of ultra-soft ground. In this study, the new ground treatment that is using cement and SCS is compared, analyzed with existing ground treatment. In addition, through the laboratory tests that check the characteristic of congealment and strength, the application of SCS in field is affirmed.

• 한국해양공학회지
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• 제16권6호
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• pp.44-48
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• 2002

In lateral ground flow, slope stability, and land slide problems, H-piles have often been used, on a horizontally deforming ground, to prevent the failure of mass of soil in a downward and outward movement of a slope. Here, theoretical equations are derived to estimate the lateral force, assuming that the Mohr-Coulomb's plastic states occur in the ground, just around H-piles. In this study, some model experiments were performed to check the lateral forces determined from theoretical equations, using several pile widths, heights and various interval ratios between H-piles for sand specimens. The solution of the theoretical equation, derived from previous studies, showed reasonable characteristics for constants of soil, as well as for the interval, widths, and heights of H-Pile.

• 한국안전학회지
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• 제9권4호
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• pp.17-28
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• 1994

Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.

• 한국지반공학회지:지반
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• 제10권3호
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• pp.111-118
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• 1994

A series of drained cubical triaxial tests was performed to investigate the finfluence of the intermediate principal stress on the deformation and strength characteristics of sand. Test results showed that the strength of sand as represented by the friction angle increased from triaxial compression condition (b:0) with increasing magnitude of the intermediate principal stress until the vus of b reached 0.75, land it decreased slightly with closing to b= 1. Also it was found that the projection of the plastic strain increment vector on the octahedral plane was perpendicular to the trace of the failure surface on that plane. The prediction by the isotropic single hardening model sllowed good coinidence with experimental results.

• 한국산학기술학회논문지
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• 제4권1호
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• pp.36-41
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• 2003

열간단조 밀폐금형의 수명연장을 위한 빌릿의 소성변형 유동해석을 유한 요소법에 의하여 실시한 결과 임프레션 형상에 대한 수정설계를 수행하였고, 임프레션 표면 마멸부위의 보수방법을 육성용접에 의한 방법으로 금형을 재생하여 사용한 결과 개발 전의 3,0(H개 생산에서 개발 후 5,000개 양산되었을 때 임프레션 표면을 관찰하였더니 3,000개 정도에서 나타났던 마멸보다 얕은 마멸이 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1024-1026
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• 2003

The purpose of establishing GPS networks of continuously operating reference stations (CORS) is aimed to assist land surveying or crustal deformation in the early stage. However, with a fast evolving and improving path the GPS technique has been extended to accurately measure atmospheric precip itable water vapor as a core objective of many projects developed in many countries and regions such as the SuomiNet (U.S., UNAVCO), COST716 (European, COST), GEONET (Japan, GSI), ...etc. In this paper, we present the current progress of the being-set-up GPS network in Taiwan whose atmospheric profile observations mainly count on the traditional radiosonde soundings as typically seen in any other part of the world. The GPS data collected from the Taiwan dense GPS network primarily supported by Central Weather Bureau are processed using the Bernese software version 4.2. Precipitable water vapor is then derived with the auxiliary surface meteorological measurements. Time series of precipitable water are examined and analyzed. A focus on the extreme weather cases is shown as an example.

• 한국지반신소재학회논문집
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• 제16권3호
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• pp.1-10
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• 2017

최근 발생하고 있는 자연재해 중 산사태와 관련된 재해는 막대한 인명과 재산피해를 발생시키고 있다. 지속적으로 발생하고 있는 산사태로 인한 피해를 최소화하기 위해서는 계측, 모니터링 시스템 등 관련 기술에 대한 과학적 관리체계가 필요하다. 본 연구는 사면붕괴 예측을 통한 산사태 피해저감을 위한 관리체계 확립을 목적으로 하고 있다. 이를 위해 산사태 발생시 지반거동을 예측하기 위한 표층지반변형률 봉을 제작하고, 사면 붕괴전조로서 변형률 증가를 관측하였다. 그 결과, 사면 붕괴시 지반의 변형은 붕괴 전조 구간, 변형 가속 구간, 변형 급가속 구간을 거친 후 붕괴에 이르는 것으로 나타나, 붕괴 전조 예측과 상관관계가 있는 것으로 판단된다. 모든 조건에서 사면붕괴 전조로서 시간에 따른 변위량의 증가가 공통적으로 관측되었으며, 이는 붕괴위험 사면의 계측 및 유지관리 관점에서 대단히 중요한 현상으로 판단된다. 산사태 발생에 따른 지반변위는 향후 지속적 연구를 통해 사면붕괴예측 및 계측관리기준의 기초자료로 활용될 수 있을 것으로 사료되며, 산사태 피해저감 및 계측산업 활성화에 기여할 수 있을 것으로 판단된다.

• 한국지반공학회논문집
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• 제38권11호
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• pp.43-54
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• 2022

철도 시설물에서는 침하 및 틀림에 의해 사고가 발생할 수 있어 변형을 적정수준으로 유지하는 것이 중요하다. 변형을 모니터링하기 위해서는 과도한 인력과 시간이 필요하기 때문에 이를 개선하기 위해 위성원격탐사 기술 중 하나인 InSAR 기술을 활용하고자 한다. 장기적인 시계열 분석을 위해서는 25장 이상의 고해상도 위성정보로 PS-InSAR 기법을 활용 할 수 있으나, 신속하고 단기적인 방법으로 2장 이상의 위성정보로 D-InSAR 기법으로 미세 변형을 관측할 수 있다. 본 연구에서는 TerraSAR-X 영상을 이용하여 D-InSAR 기법을 적용하여 오송 철도종합시험선로의 지반 침하량 및 구조물 변형량을 구하였다. 구조물과 사면에 반사강도를 높일 수 있는 코너리플렉터를 인공적으로 설치하여 변위 값을 임의로 수 mm 조정하여 이를 검증 할 수 있도록 하였다. D-InSAR 분석 결과로부터 적절한 코너리플렉터 배치도를 산출하였고, 궤도, 사면, 구조물 구역의 변위량을 측정하였다. 더불어 임의로 조정한 코너리플렉터의 변위값을 D-InSAR 분석으로 산출하였다. 본 연구 결과로부터 D-InSAR 결과를 철도시설물과 같은 광범위한 인프라 시설에 모니터링을 위한 기법으로 활용 가능함을 확인하였다.